Commit Graph

1375 Commits

Author SHA1 Message Date
Steven Rostedt (Google)
1ef26d8b2c tracing: Use the new eventfs descriptor for print trigger
The check to create the print event "trigger" was using the obsolete "dir"
value of the trace_event_file to determine if it should create the trigger
or not. But that value will now be NULL because it uses the event file
descriptor.

Change it to test the "ef" field of the trace_event_file structure so that
the trace_marker "trigger" file appears again.

Link: https://lkml.kernel.org/r/20230908022001.371815239@goodmis.org

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ajay Kaher <akaher@vmware.com>
Fixes: 27152bceea ("eventfs: Move tracing/events to eventfs")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-09-08 23:13:01 -04:00
Steven Rostedt (Google)
7e2cfbd2d3 tracing: Have option files inc the trace array ref count
The option files update the options for a given trace array. For an
instance, if the file is opened and the instance is deleted, reading or
writing to the file will cause a use after free.

Up the ref count of the trace_array when an option file is opened.

Link: https://lkml.kernel.org/r/20230907024804.086679464@goodmis.org
Link: https://lore.kernel.org/all/1cb3aee2-19af-c472-e265-05176fe9bd84@huawei.com/

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Zheng Yejian <zhengyejian1@huawei.com>
Fixes: 8530dec63e ("tracing: Add tracing_check_open_get_tr()")
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-09-07 16:38:54 -04:00
Steven Rostedt (Google)
9b37febc57 tracing: Have current_trace inc the trace array ref count
The current_trace updates the trace array tracer. For an instance, if the
file is opened and the instance is deleted, reading or writing to the file
will cause a use after free.

Up the ref count of the trace array when current_trace is opened.

Link: https://lkml.kernel.org/r/20230907024803.877687227@goodmis.org
Link: https://lore.kernel.org/all/1cb3aee2-19af-c472-e265-05176fe9bd84@huawei.com/

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Zheng Yejian <zhengyejian1@huawei.com>
Fixes: 8530dec63e ("tracing: Add tracing_check_open_get_tr()")
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-09-07 16:38:53 -04:00
Steven Rostedt (Google)
7d660c9b2b tracing: Have tracing_max_latency inc the trace array ref count
The tracing_max_latency file points to the trace_array max_latency field.
For an instance, if the file is opened and the instance is deleted,
reading or writing to the file will cause a use after free.

Up the ref count of the trace_array when tracing_max_latency is opened.

Link: https://lkml.kernel.org/r/20230907024803.666889383@goodmis.org
Link: https://lore.kernel.org/all/1cb3aee2-19af-c472-e265-05176fe9bd84@huawei.com/

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Zheng Yejian <zhengyejian1@huawei.com>
Fixes: 8530dec63e ("tracing: Add tracing_check_open_get_tr()")
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-09-07 16:38:53 -04:00
Steven Rostedt (Google)
f5ca233e2e tracing: Increase trace array ref count on enable and filter files
When the trace event enable and filter files are opened, increment the
trace array ref counter, otherwise they can be accessed when the trace
array is being deleted. The ref counter keeps the trace array from being
deleted while those files are opened.

Link: https://lkml.kernel.org/r/20230907024803.456187066@goodmis.org
Link: https://lore.kernel.org/all/1cb3aee2-19af-c472-e265-05176fe9bd84@huawei.com/

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 8530dec63e ("tracing: Add tracing_check_open_get_tr()")
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Reported-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-09-07 16:05:46 -04:00
Linus Torvalds
b70100f2e6 Probes updates for v6.6:
- kprobes: use struct_size() for variable size kretprobe_instance
   data structure.
 
 - eprobe: Simplify trace_eprobe list iteration.
 
 - probe events: Data structure field access support on BTF argument.
   . Update BTF argument support on the functions in the kernel loadable
     modules (only loaded modules are supported).
   . Move generic BTF access function (search function prototype and get
     function parameters) to a separated file.
   . Add a function to search a member of data structure in BTF.
   . Support accessing BTF data structure member from probe args by
     C-like arrow('->') and dot('.') operators. e.g.
     't sched_switch next=next->pid vruntime=next->se.vruntime'
   . Support accessing BTF data structure member from $retval. e.g.
       'f getname_flags%return +0($retval->name):string'
   . Add string type checking if BTF type info is available.
     This will reject if user specify ":string" type for non "char
     pointer" type.
   . Automatically assume the fprobe event as a function return event
     if $retval is used.
 
 - selftests/ftrace: Add BTF data field access test cases.
 
 - Documentation: Update fprobe event example with BTF data field.
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Merge tag 'probes-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull probes updates from Masami Hiramatsu:

 - kprobes: use struct_size() for variable size kretprobe_instance data
   structure.

 - eprobe: Simplify trace_eprobe list iteration.

 - probe events: Data structure field access support on BTF argument.

     - Update BTF argument support on the functions in the kernel
       loadable modules (only loaded modules are supported).

     - Move generic BTF access function (search function prototype and
       get function parameters) to a separated file.

     - Add a function to search a member of data structure in BTF.

     - Support accessing BTF data structure member from probe args by
       C-like arrow('->') and dot('.') operators. e.g.
          't sched_switch next=next->pid vruntime=next->se.vruntime'

     - Support accessing BTF data structure member from $retval. e.g.
          'f getname_flags%return +0($retval->name):string'

     - Add string type checking if BTF type info is available. This will
       reject if user specify ":string" type for non "char pointer"
       type.

     - Automatically assume the fprobe event as a function return event
       if $retval is used.

 - selftests/ftrace: Add BTF data field access test cases.

 - Documentation: Update fprobe event example with BTF data field.

* tag 'probes-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  Documentation: tracing: Update fprobe event example with BTF field
  selftests/ftrace: Add BTF fields access testcases
  tracing/fprobe-event: Assume fprobe is a return event by $retval
  tracing/probes: Add string type check with BTF
  tracing/probes: Support BTF field access from $retval
  tracing/probes: Support BTF based data structure field access
  tracing/probes: Add a function to search a member of a struct/union
  tracing/probes: Move finding func-proto API and getting func-param API to trace_btf
  tracing/probes: Support BTF argument on module functions
  tracing/eprobe: Iterate trace_eprobe directly
  kernel: kprobes: Use struct_size()
2023-09-02 11:10:50 -07:00
Brian Foster
3d07fa1dd1 tracing: Zero the pipe cpumask on alloc to avoid spurious -EBUSY
The pipe cpumask used to serialize opens between the main and percpu
trace pipes is not zeroed or initialized. This can result in
spurious -EBUSY returns if underlying memory is not fully zeroed.
This has been observed by immediate failure to read the main
trace_pipe file on an otherwise newly booted and idle system:

 # cat /sys/kernel/debug/tracing/trace_pipe
 cat: /sys/kernel/debug/tracing/trace_pipe: Device or resource busy

Zero the allocation of pipe_cpumask to avoid the problem.

Link: https://lore.kernel.org/linux-trace-kernel/20230831125500.986862-1-bfoster@redhat.com

Cc: stable@vger.kernel.org
Fixes: c2489bb7e6 ("tracing: Introduce pipe_cpumask to avoid race on trace_pipes")
Reviewed-by: Zheng Yejian <zhengyejian1@huawei.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-09-01 21:26:07 -04:00
Zheng Yejian
3163f635b2 tracing: Fix race issue between cpu buffer write and swap
Warning happened in rb_end_commit() at code:
	if (RB_WARN_ON(cpu_buffer, !local_read(&cpu_buffer->committing)))

  WARNING: CPU: 0 PID: 139 at kernel/trace/ring_buffer.c:3142
	rb_commit+0x402/0x4a0
  Call Trace:
   ring_buffer_unlock_commit+0x42/0x250
   trace_buffer_unlock_commit_regs+0x3b/0x250
   trace_event_buffer_commit+0xe5/0x440
   trace_event_buffer_reserve+0x11c/0x150
   trace_event_raw_event_sched_switch+0x23c/0x2c0
   __traceiter_sched_switch+0x59/0x80
   __schedule+0x72b/0x1580
   schedule+0x92/0x120
   worker_thread+0xa0/0x6f0

It is because the race between writing event into cpu buffer and swapping
cpu buffer through file per_cpu/cpu0/snapshot:

  Write on CPU 0             Swap buffer by per_cpu/cpu0/snapshot on CPU 1
  --------                   --------
                             tracing_snapshot_write()
                               [...]

  ring_buffer_lock_reserve()
    cpu_buffer = buffer->buffers[cpu]; // 1. Suppose find 'cpu_buffer_a';
    [...]
    rb_reserve_next_event()
      [...]

                               ring_buffer_swap_cpu()
                                 if (local_read(&cpu_buffer_a->committing))
                                     goto out_dec;
                                 if (local_read(&cpu_buffer_b->committing))
                                     goto out_dec;
                                 buffer_a->buffers[cpu] = cpu_buffer_b;
                                 buffer_b->buffers[cpu] = cpu_buffer_a;
                                 // 2. cpu_buffer has swapped here.

      rb_start_commit(cpu_buffer);
      if (unlikely(READ_ONCE(cpu_buffer->buffer)
          != buffer)) { // 3. This check passed due to 'cpu_buffer->buffer'
        [...]           //    has not changed here.
        return NULL;
      }
                                 cpu_buffer_b->buffer = buffer_a;
                                 cpu_buffer_a->buffer = buffer_b;
                                 [...]

      // 4. Reserve event from 'cpu_buffer_a'.

  ring_buffer_unlock_commit()
    [...]
    cpu_buffer = buffer->buffers[cpu]; // 5. Now find 'cpu_buffer_b' !!!
    rb_commit(cpu_buffer)
      rb_end_commit()  // 6. WARN for the wrong 'committing' state !!!

Based on above analysis, we can easily reproduce by following testcase:
  ``` bash
  #!/bin/bash

  dmesg -n 7
  sysctl -w kernel.panic_on_warn=1
  TR=/sys/kernel/tracing
  echo 7 > ${TR}/buffer_size_kb
  echo "sched:sched_switch" > ${TR}/set_event
  while [ true ]; do
          echo 1 > ${TR}/per_cpu/cpu0/snapshot
  done &
  while [ true ]; do
          echo 1 > ${TR}/per_cpu/cpu0/snapshot
  done &
  while [ true ]; do
          echo 1 > ${TR}/per_cpu/cpu0/snapshot
  done &
  ```

To fix it, IIUC, we can use smp_call_function_single() to do the swap on
the target cpu where the buffer is located, so that above race would be
avoided.

Link: https://lore.kernel.org/linux-trace-kernel/20230831132739.4070878-1-zhengyejian1@huawei.com

Cc: <mhiramat@kernel.org>
Fixes: f1affcaaa8 ("tracing: Add snapshot in the per_cpu trace directories")
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-09-01 21:00:00 -04:00
Linus Torvalds
34232fcfe9 Tracing updates for 6.6:
User visible changes:
 
   - Added a way to easier filter with cpumasks:
      # echo 'cpumask & CPUS{17-42}' > /sys/kernel/tracing/events/ipi_send_cpumask/filter
 
   - Show actual size of ring buffer after modifying the ring buffer size via
     buffer_size_kb. Currently it just returns what was written, but the actual
     size rounds up to the sub buffer size. Show that real size instead.
 
  Major changes:
 
   - Added "eventfs". This is the code that handles the inodes and dentries of
     tracefs/events directory. As there are thousands of events, and each event
     has several inodes and dentries that currently exist even when tracing is
     never used, they take up precious memory. Instead, eventfs will allocate
     the inodes and dentries in a JIT way (similar to what procfs does). There
     is now metadata that handles the events and subdirectories, and will create
     the inodes and dentries when they are used.
 
     Note, I also have patches that remove the subdirectory meta data, but will
     wait till the next merge window before applying them. It's a little more
     complex, and I want to make sure the dynamic code works properly before
     adding more complexity, making it easier to revert if need be.
 
  Minor changes:
 
   - Optimization to user event list traversal.
 
   - Remove intermediate permission of tracefs files (note the intermediate
     permission removes all access to the files so it is not a security concern,
     but just a clean up.)
 
   - Add the complex fix to FORTIFY_SOURCE to the kernel stack event logic.
 
   - Other minor clean ups.
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Merge tag 'trace-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt:
 "User visible changes:

   - Added a way to easier filter with cpumasks:

       # echo 'cpumask & CPUS{17-42}' > /sys/kernel/tracing/events/ipi_send_cpumask/filter

   - Show actual size of ring buffer after modifying the ring buffer
     size via buffer_size_kb.

     Currently it just returns what was written, but the actual size
     rounds up to the sub buffer size. Show that real size instead.

  Major changes:

   - Added "eventfs". This is the code that handles the inodes and
     dentries of tracefs/events directory. As there are thousands of
     events, and each event has several inodes and dentries that
     currently exist even when tracing is never used, they take up
     precious memory. Instead, eventfs will allocate the inodes and
     dentries in a JIT way (similar to what procfs does). There is now
     metadata that handles the events and subdirectories, and will
     create the inodes and dentries when they are used.

     Note, I also have patches that remove the subdirectory meta data,
     but will wait till the next merge window before applying them. It's
     a little more complex, and I want to make sure the dynamic code
     works properly before adding more complexity, making it easier to
     revert if need be.

  Minor changes:

   - Optimization to user event list traversal

   - Remove intermediate permission of tracefs files (note the
     intermediate permission removes all access to the files so it is
     not a security concern, but just a clean up)

   - Add the complex fix to FORTIFY_SOURCE to the kernel stack event
     logic

   - Other minor cleanups"

* tag 'trace-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (29 commits)
  tracefs: Remove kerneldoc from struct eventfs_file
  tracefs: Avoid changing i_mode to a temp value
  tracing/user_events: Optimize safe list traversals
  ftrace: Remove empty declaration ftrace_enable_daemon() and ftrace_disable_daemon()
  tracing: Remove unused function declarations
  tracing/filters: Document cpumask filtering
  tracing/filters: Further optimise scalar vs cpumask comparison
  tracing/filters: Optimise CPU vs cpumask filtering when the user mask is a single CPU
  tracing/filters: Optimise scalar vs cpumask filtering when the user mask is a single CPU
  tracing/filters: Optimise cpumask vs cpumask filtering when user mask is a single CPU
  tracing/filters: Enable filtering the CPU common field by a cpumask
  tracing/filters: Enable filtering a scalar field by a cpumask
  tracing/filters: Enable filtering a cpumask field by another cpumask
  tracing/filters: Dynamically allocate filter_pred.regex
  test: ftrace: Fix kprobe test for eventfs
  eventfs: Move tracing/events to eventfs
  eventfs: Implement removal of meta data from eventfs
  eventfs: Implement functions to create files and dirs when accessed
  eventfs: Implement eventfs lookup, read, open functions
  eventfs: Implement eventfs file add functions
  ...
2023-09-01 16:34:25 -07:00
Masami Hiramatsu (Google)
c440adfbe3 tracing/probes: Support BTF based data structure field access
Using BTF to access the fields of a data structure. You can use this
for accessing the field with '->' or '.' operation with BTF argument.

 # echo 't sched_switch next=next->pid vruntime=next->se.vruntime' \
   > dynamic_events
 # echo 1 > events/tracepoints/sched_switch/enable
 # head -n 40 trace | tail
          <idle>-0       [000] d..3.   272.565382: sched_switch: (__probestub_sched_switch+0x4/0x10) next=26 vruntime=956533179
      kcompactd0-26      [000] d..3.   272.565406: sched_switch: (__probestub_sched_switch+0x4/0x10) next=0 vruntime=0
          <idle>-0       [000] d..3.   273.069441: sched_switch: (__probestub_sched_switch+0x4/0x10) next=9 vruntime=956533179
     kworker/0:1-9       [000] d..3.   273.069464: sched_switch: (__probestub_sched_switch+0x4/0x10) next=26 vruntime=956579181
      kcompactd0-26      [000] d..3.   273.069480: sched_switch: (__probestub_sched_switch+0x4/0x10) next=0 vruntime=0
          <idle>-0       [000] d..3.   273.141434: sched_switch: (__probestub_sched_switch+0x4/0x10) next=22 vruntime=956533179
    kworker/u2:1-22      [000] d..3.   273.141461: sched_switch: (__probestub_sched_switch+0x4/0x10) next=0 vruntime=0
          <idle>-0       [000] d..3.   273.480872: sched_switch: (__probestub_sched_switch+0x4/0x10) next=22 vruntime=956585857
    kworker/u2:1-22      [000] d..3.   273.480905: sched_switch: (__probestub_sched_switch+0x4/0x10) next=70 vruntime=959533179
              sh-70      [000] d..3.   273.481102: sched_switch: (__probestub_sched_switch+0x4/0x10) next=0 vruntime=0

Link: https://lore.kernel.org/all/169272157251.160970.9318175874130965571.stgit@devnote2/

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-08-23 09:40:28 +09:00
Zheng Yejian
c2489bb7e6 tracing: Introduce pipe_cpumask to avoid race on trace_pipes
There is race issue when concurrently splice_read main trace_pipe and
per_cpu trace_pipes which will result in data read out being different
from what actually writen.

As suggested by Steven:
  > I believe we should add a ref count to trace_pipe and the per_cpu
  > trace_pipes, where if they are opened, nothing else can read it.
  >
  > Opening trace_pipe locks all per_cpu ref counts, if any of them are
  > open, then the trace_pipe open will fail (and releases any ref counts
  > it had taken).
  >
  > Opening a per_cpu trace_pipe will up the ref count for just that
  > CPU buffer. This will allow multiple tasks to read different per_cpu
  > trace_pipe files, but will prevent the main trace_pipe file from
  > being opened.

But because we only need to know whether per_cpu trace_pipe is open or
not, using a cpumask instead of using ref count may be easier.

After this patch, users will find that:
 - Main trace_pipe can be opened by only one user, and if it is
   opened, all per_cpu trace_pipes cannot be opened;
 - Per_cpu trace_pipes can be opened by multiple users, but each per_cpu
   trace_pipe can only be opened by one user. And if one of them is
   opened, main trace_pipe cannot be opened.

Link: https://lore.kernel.org/linux-trace-kernel/20230818022645.1948314-1-zhengyejian1@huawei.com

Suggested-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-08-21 11:17:14 -04:00
Zheng Yejian
eecb91b9f9 tracing: Fix memleak due to race between current_tracer and trace
Kmemleak report a leak in graph_trace_open():

  unreferenced object 0xffff0040b95f4a00 (size 128):
    comm "cat", pid 204981, jiffies 4301155872 (age 99771.964s)
    hex dump (first 32 bytes):
      e0 05 e7 b4 ab 7d 00 00 0b 00 01 00 00 00 00 00 .....}..........
      f4 00 01 10 00 a0 ff ff 00 00 00 00 65 00 10 00 ............e...
    backtrace:
      [<000000005db27c8b>] kmem_cache_alloc_trace+0x348/0x5f0
      [<000000007df90faa>] graph_trace_open+0xb0/0x344
      [<00000000737524cd>] __tracing_open+0x450/0xb10
      [<0000000098043327>] tracing_open+0x1a0/0x2a0
      [<00000000291c3876>] do_dentry_open+0x3c0/0xdc0
      [<000000004015bcd6>] vfs_open+0x98/0xd0
      [<000000002b5f60c9>] do_open+0x520/0x8d0
      [<00000000376c7820>] path_openat+0x1c0/0x3e0
      [<00000000336a54b5>] do_filp_open+0x14c/0x324
      [<000000002802df13>] do_sys_openat2+0x2c4/0x530
      [<0000000094eea458>] __arm64_sys_openat+0x130/0x1c4
      [<00000000a71d7881>] el0_svc_common.constprop.0+0xfc/0x394
      [<00000000313647bf>] do_el0_svc+0xac/0xec
      [<000000002ef1c651>] el0_svc+0x20/0x30
      [<000000002fd4692a>] el0_sync_handler+0xb0/0xb4
      [<000000000c309c35>] el0_sync+0x160/0x180

The root cause is descripted as follows:

  __tracing_open() {  // 1. File 'trace' is being opened;
    ...
    *iter->trace = *tr->current_trace;  // 2. Tracer 'function_graph' is
                                        //    currently set;
    ...
    iter->trace->open(iter);  // 3. Call graph_trace_open() here,
                              //    and memory are allocated in it;
    ...
  }

  s_start() {  // 4. The opened file is being read;
    ...
    *iter->trace = *tr->current_trace;  // 5. If tracer is switched to
                                        //    'nop' or others, then memory
                                        //    in step 3 are leaked!!!
    ...
  }

To fix it, in s_start(), close tracer before switching then reopen the
new tracer after switching. And some tracers like 'wakeup' may not update
'iter->private' in some cases when reopen, then it should be cleared
to avoid being mistakenly closed again.

Link: https://lore.kernel.org/linux-trace-kernel/20230817125539.1646321-1-zhengyejian1@huawei.com

Fixes: d7350c3f45 ("tracing/core: make the read callbacks reentrants")
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-08-17 13:49:37 -04:00
Zheng Yejian
b71645d6af tracing: Fix cpu buffers unavailable due to 'record_disabled' missed
Trace ring buffer can no longer record anything after executing
following commands at the shell prompt:

  # cd /sys/kernel/tracing
  # cat tracing_cpumask
  fff
  # echo 0 > tracing_cpumask
  # echo 1 > snapshot
  # echo fff > tracing_cpumask
  # echo 1 > tracing_on
  # echo "hello world" > trace_marker
  -bash: echo: write error: Bad file descriptor

The root cause is that:
  1. After `echo 0 > tracing_cpumask`, 'record_disabled' of cpu buffers
     in 'tr->array_buffer.buffer' became 1 (see tracing_set_cpumask());
  2. After `echo 1 > snapshot`, 'tr->array_buffer.buffer' is swapped
     with 'tr->max_buffer.buffer', then the 'record_disabled' became 0
     (see update_max_tr());
  3. After `echo fff > tracing_cpumask`, the 'record_disabled' become -1;
Then array_buffer and max_buffer are both unavailable due to value of
'record_disabled' is not 0.

To fix it, enable or disable both array_buffer and max_buffer at the same
time in tracing_set_cpumask().

Link: https://lkml.kernel.org/r/20230805033816.3284594-2-zhengyejian1@huawei.com

Cc: <mhiramat@kernel.org>
Cc: <vnagarnaik@google.com>
Cc: <shuah@kernel.org>
Fixes: 71babb2705 ("tracing: change CPU ring buffer state from tracing_cpumask")
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-08-16 15:12:42 -04:00
Zheng Yejian
6d98a0f2ac tracing: Set actual size after ring buffer resize
Currently we can resize trace ringbuffer by writing a value into file
'buffer_size_kb', then by reading the file, we get the value that is
usually what we wrote. However, this value may be not actual size of
trace ring buffer because of the round up when doing resize in kernel,
and the actual size would be more useful.

Link: https://lore.kernel.org/linux-trace-kernel/20230705002705.576633-1-zhengyejian1@huawei.com

Cc: <mhiramat@kernel.org>
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-07-30 18:11:45 -04:00
Steven Rostedt (Google)
6bba92881d tracing: Add free_trace_iter_content() helper function
As the trace iterator is created and used by various interfaces, the clean
up of it needs to be consistent. Create a free_trace_iter_content() helper
function that frees the content of the iterator and use that to clean it
up in all places that it is used.

Link: https://lkml.kernel.org/r/20230715141348.341887497@goodmis.org

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-07-30 18:11:45 -04:00
Steven Rostedt (Google)
9182b519b8 tracing: Remove unnecessary copying of tr->current_trace
The iterator allocated a descriptor to copy the current_trace. This was done
with the assumption that the function pointers might change. But this was a
false assuption, as it does not change. There's no reason to make a copy of the
current_trace and just use the pointer it points to. This removes needing to
manage freeing the descriptor. Worse yet, there's locations that the iterator
is used but does make a copy and just uses the pointer. This could cause the
actual pointer to the trace descriptor to be freed and not the allocated copy.

This is more of a clean up than a fix.

Link: https://lkml.kernel.org/r/20230715141348.135792275@goodmis.org

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: d7350c3f45 ("tracing/core: make the read callbacks reentrants")
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-07-30 18:11:45 -04:00
Steven Rostedt (Google)
e7186af7fb tracing: Add back FORTIFY_SOURCE logic to kernel_stack event structure
For backward compatibility, older tooling expects to see the kernel_stack
event with a "caller" field that is a fixed size array of 8 addresses. The
code now supports more than 8 with an added "size" field that states the
real number of entries. But the "caller" field still just looks like a
fixed size to user space.

Since the tracing macros that create the user space format files also
creates the structures that those files represent, the kernel_stack event
structure had its "caller" field a fixed size of 8, but in reality, when
it is allocated on the ring buffer, it can hold more if the stack trace is
bigger that 8 functions. The copying of these entries was simply done with
a memcpy():

  size = nr_entries * sizeof(unsigned long);
  memcpy(entry->caller, fstack->calls, size);

The FORTIFY_SOURCE logic noticed at runtime that when the nr_entries was
larger than 8, that the memcpy() was writing more than what the structure
stated it can hold and it complained about it. This is because the
FORTIFY_SOURCE code is unaware that the amount allocated is actually
enough to hold the size. It does not expect that a fixed size field will
hold more than the fixed size.

This was originally solved by hiding the caller assignment with some
pointer arithmetic.

  ptr = ring_buffer_data();
  entry = ptr;

  ptr += offsetof(typeof(*entry), caller);
  memcpy(ptr, fstack->calls, size);

But it is considered bad form to hide from kernel hardening. Instead, make
it work nicely with FORTIFY_SOURCE by adding a new __stack_array() macro
that is specific for this one special use case. The macro will take 4
arguments: type, item, len, field (whereas the __array() macro takes just
the first three). This macro will act just like the __array() macro when
creating the code to deal with the format file that is exposed to user
space. But for the kernel, it will turn the caller field into:

  type item[] __counted_by(field);

or for this instance:

  unsigned long caller[] __counted_by(size);

Now the kernel code can expose the assignment of the caller to the
FORTIFY_SOURCE and everyone is happy!

Link: https://lore.kernel.org/linux-trace-kernel/20230712105235.5fc441aa@gandalf.local.home/
Link: https://lore.kernel.org/linux-trace-kernel/20230713092605.2ddb9788@rorschach.local.home

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
2023-07-30 18:11:44 -04:00
Chen Lin
8a96c0288d ring-buffer: Do not swap cpu_buffer during resize process
When ring_buffer_swap_cpu was called during resize process,
the cpu buffer was swapped in the middle, resulting in incorrect state.
Continuing to run in the wrong state will result in oops.

This issue can be easily reproduced using the following two scripts:
/tmp # cat test1.sh
//#! /bin/sh
for i in `seq 0 100000`
do
         echo 2000 > /sys/kernel/debug/tracing/buffer_size_kb
         sleep 0.5
         echo 5000 > /sys/kernel/debug/tracing/buffer_size_kb
         sleep 0.5
done
/tmp # cat test2.sh
//#! /bin/sh
for i in `seq 0 100000`
do
        echo irqsoff > /sys/kernel/debug/tracing/current_tracer
        sleep 1
        echo nop > /sys/kernel/debug/tracing/current_tracer
        sleep 1
done
/tmp # ./test1.sh &
/tmp # ./test2.sh &

A typical oops log is as follows, sometimes with other different oops logs.

[  231.711293] WARNING: CPU: 0 PID: 9 at kernel/trace/ring_buffer.c:2026 rb_update_pages+0x378/0x3f8
[  231.713375] Modules linked in:
[  231.714735] CPU: 0 PID: 9 Comm: kworker/0:1 Tainted: G        W          6.5.0-rc1-00276-g20edcec23f92 #15
[  231.716750] Hardware name: linux,dummy-virt (DT)
[  231.718152] Workqueue: events update_pages_handler
[  231.719714] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[  231.721171] pc : rb_update_pages+0x378/0x3f8
[  231.722212] lr : rb_update_pages+0x25c/0x3f8
[  231.723248] sp : ffff800082b9bd50
[  231.724169] x29: ffff800082b9bd50 x28: ffff8000825f7000 x27: 0000000000000000
[  231.726102] x26: 0000000000000001 x25: fffffffffffff010 x24: 0000000000000ff0
[  231.728122] x23: ffff0000c3a0b600 x22: ffff0000c3a0b5c0 x21: fffffffffffffe0a
[  231.730203] x20: ffff0000c3a0b600 x19: ffff0000c0102400 x18: 0000000000000000
[  231.732329] x17: 0000000000000000 x16: 0000000000000000 x15: 0000ffffe7aa8510
[  231.734212] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000002
[  231.736291] x11: ffff8000826998a8 x10: ffff800082b9baf0 x9 : ffff800081137558
[  231.738195] x8 : fffffc00030e82c8 x7 : 0000000000000000 x6 : 0000000000000001
[  231.740192] x5 : ffff0000ffbafe00 x4 : 0000000000000000 x3 : 0000000000000000
[  231.742118] x2 : 00000000000006aa x1 : 0000000000000001 x0 : ffff0000c0007208
[  231.744196] Call trace:
[  231.744892]  rb_update_pages+0x378/0x3f8
[  231.745893]  update_pages_handler+0x1c/0x38
[  231.746893]  process_one_work+0x1f0/0x468
[  231.747852]  worker_thread+0x54/0x410
[  231.748737]  kthread+0x124/0x138
[  231.749549]  ret_from_fork+0x10/0x20
[  231.750434] ---[ end trace 0000000000000000 ]---
[  233.720486] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
[  233.721696] Mem abort info:
[  233.721935]   ESR = 0x0000000096000004
[  233.722283]   EC = 0x25: DABT (current EL), IL = 32 bits
[  233.722596]   SET = 0, FnV = 0
[  233.722805]   EA = 0, S1PTW = 0
[  233.723026]   FSC = 0x04: level 0 translation fault
[  233.723458] Data abort info:
[  233.723734]   ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
[  233.724176]   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
[  233.724589]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[  233.725075] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000104943000
[  233.725592] [0000000000000000] pgd=0000000000000000, p4d=0000000000000000
[  233.726231] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
[  233.726720] Modules linked in:
[  233.727007] CPU: 0 PID: 9 Comm: kworker/0:1 Tainted: G        W          6.5.0-rc1-00276-g20edcec23f92 #15
[  233.727777] Hardware name: linux,dummy-virt (DT)
[  233.728225] Workqueue: events update_pages_handler
[  233.728655] pstate: 200000c5 (nzCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[  233.729054] pc : rb_update_pages+0x1a8/0x3f8
[  233.729334] lr : rb_update_pages+0x154/0x3f8
[  233.729592] sp : ffff800082b9bd50
[  233.729792] x29: ffff800082b9bd50 x28: ffff8000825f7000 x27: 0000000000000000
[  233.730220] x26: 0000000000000000 x25: ffff800082a8b840 x24: ffff0000c0102418
[  233.730653] x23: 0000000000000000 x22: fffffc000304c880 x21: 0000000000000003
[  233.731105] x20: 00000000000001f4 x19: ffff0000c0102400 x18: ffff800082fcbc58
[  233.731727] x17: 0000000000000000 x16: 0000000000000001 x15: 0000000000000001
[  233.732282] x14: ffff8000825fe0c8 x13: 0000000000000001 x12: 0000000000000000
[  233.732709] x11: ffff8000826998a8 x10: 0000000000000ae0 x9 : ffff8000801b760c
[  233.733148] x8 : fefefefefefefeff x7 : 0000000000000018 x6 : ffff0000c03298c0
[  233.733553] x5 : 0000000000000002 x4 : 0000000000000000 x3 : 0000000000000000
[  233.733972] x2 : ffff0000c3a0b600 x1 : 0000000000000000 x0 : 0000000000000000
[  233.734418] Call trace:
[  233.734593]  rb_update_pages+0x1a8/0x3f8
[  233.734853]  update_pages_handler+0x1c/0x38
[  233.735148]  process_one_work+0x1f0/0x468
[  233.735525]  worker_thread+0x54/0x410
[  233.735852]  kthread+0x124/0x138
[  233.736064]  ret_from_fork+0x10/0x20
[  233.736387] Code: 92400000 910006b5 aa000021 aa0303f7 (f9400060)
[  233.736959] ---[ end trace 0000000000000000 ]---

After analysis, the seq of the error is as follows [1-5]:

int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size,
			int cpu_id)
{
	for_each_buffer_cpu(buffer, cpu) {
		cpu_buffer = buffer->buffers[cpu];
		//1. get cpu_buffer, aka cpu_buffer(A)
		...
		...
		schedule_work_on(cpu,
		 &cpu_buffer->update_pages_work);
		//2. 'update_pages_work' is queue on 'cpu', cpu_buffer(A) is passed to
		// update_pages_handler, do the update process, set 'update_done' in
		// complete(&cpu_buffer->update_done) and to wakeup resize process.
	//---->
		//3. Just at this moment, ring_buffer_swap_cpu is triggered,
		//cpu_buffer(A) be swaped to cpu_buffer(B), the max_buffer.
		//ring_buffer_swap_cpu is called as the 'Call trace' below.

		Call trace:
		 dump_backtrace+0x0/0x2f8
		 show_stack+0x18/0x28
		 dump_stack+0x12c/0x188
		 ring_buffer_swap_cpu+0x2f8/0x328
		 update_max_tr_single+0x180/0x210
		 check_critical_timing+0x2b4/0x2c8
		 tracer_hardirqs_on+0x1c0/0x200
		 trace_hardirqs_on+0xec/0x378
		 el0_svc_common+0x64/0x260
		 do_el0_svc+0x90/0xf8
		 el0_svc+0x20/0x30
		 el0_sync_handler+0xb0/0xb8
		 el0_sync+0x180/0x1c0
	//<----

	/* wait for all the updates to complete */
	for_each_buffer_cpu(buffer, cpu) {
		cpu_buffer = buffer->buffers[cpu];
		//4. get cpu_buffer, cpu_buffer(B) is used in the following process,
		//the state of cpu_buffer(A) and cpu_buffer(B) is totally wrong.
		//for example, cpu_buffer(A)->update_done will leave be set 1, and will
		//not 'wait_for_completion' at the next resize round.
		  if (!cpu_buffer->nr_pages_to_update)
			continue;

		if (cpu_online(cpu))
			wait_for_completion(&cpu_buffer->update_done);
		cpu_buffer->nr_pages_to_update = 0;
	}
	...
}
	//5. the state of cpu_buffer(A) and cpu_buffer(B) is totally wrong,
	//Continuing to run in the wrong state, then oops occurs.

Link: https://lore.kernel.org/linux-trace-kernel/202307191558478409990@zte.com.cn

Signed-off-by: Chen Lin <chen.lin5@zte.com.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-07-23 11:09:25 -04:00
Zheng Yejian
d5a8218963 tracing: Fix memory leak of iter->temp when reading trace_pipe
kmemleak reports:
  unreferenced object 0xffff88814d14e200 (size 256):
    comm "cat", pid 336, jiffies 4294871818 (age 779.490s)
    hex dump (first 32 bytes):
      04 00 01 03 00 00 00 00 08 00 00 00 00 00 00 00  ................
      0c d8 c8 9b ff ff ff ff 04 5a ca 9b ff ff ff ff  .........Z......
    backtrace:
      [<ffffffff9bdff18f>] __kmalloc+0x4f/0x140
      [<ffffffff9bc9238b>] trace_find_next_entry+0xbb/0x1d0
      [<ffffffff9bc9caef>] trace_print_lat_context+0xaf/0x4e0
      [<ffffffff9bc94490>] print_trace_line+0x3e0/0x950
      [<ffffffff9bc95499>] tracing_read_pipe+0x2d9/0x5a0
      [<ffffffff9bf03a43>] vfs_read+0x143/0x520
      [<ffffffff9bf04c2d>] ksys_read+0xbd/0x160
      [<ffffffff9d0f0edf>] do_syscall_64+0x3f/0x90
      [<ffffffff9d2000aa>] entry_SYSCALL_64_after_hwframe+0x6e/0xd8

when reading file 'trace_pipe', 'iter->temp' is allocated or relocated
in trace_find_next_entry() but not freed before 'trace_pipe' is closed.

To fix it, free 'iter->temp' in tracing_release_pipe().

Link: https://lore.kernel.org/linux-trace-kernel/20230713141435.1133021-1-zhengyejian1@huawei.com

Cc: stable@vger.kernel.org
Fixes: ff895103a8 ("tracing: Save off entry when peeking at next entry")
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-07-13 10:48:36 -04:00
Steven Rostedt (Google)
bec3c25c24 tracing: Stop FORTIFY_SOURCE complaining about stack trace caller
The stack_trace event is an event created by the tracing subsystem to
store stack traces. It originally just contained a hard coded array of 8
words to hold the stack, and a "size" to know how many entries are there.
This is exported to user space as:

name: kernel_stack
ID: 4
format:
	field:unsigned short common_type;	offset:0;	size:2;	signed:0;
	field:unsigned char common_flags;	offset:2;	size:1;	signed:0;
	field:unsigned char common_preempt_count;	offset:3;	size:1;	signed:0;
	field:int common_pid;	offset:4;	size:4;	signed:1;

	field:int size;	offset:8;	size:4;	signed:1;
	field:unsigned long caller[8];	offset:16;	size:64;	signed:0;

print fmt: "\t=> %ps\n\t=> %ps\n\t=> %ps\n" "\t=> %ps\n\t=> %ps\n\t=> %ps\n" "\t=> %ps\n\t=> %ps\n",i
 (void *)REC->caller[0], (void *)REC->caller[1], (void *)REC->caller[2],
 (void *)REC->caller[3], (void *)REC->caller[4], (void *)REC->caller[5],
 (void *)REC->caller[6], (void *)REC->caller[7]

Where the user space tracers could parse the stack. The library was
updated for this specific event to only look at the size, and not the
array. But some older users still look at the array (note, the older code
still checks to make sure the array fits inside the event that it read.
That is, if only 4 words were saved, the parser would not read the fifth
word because it will see that it was outside of the event size).

This event was changed a while ago to be more dynamic, and would save a
full stack even if it was greater than 8 words. It does this by simply
allocating more ring buffer to hold the extra words. Then it copies in the
stack via:

	memcpy(&entry->caller, fstack->calls, size);

As the entry is struct stack_entry, that is created by a macro to both
create the structure and export this to user space, it still had the caller
field of entry defined as: unsigned long caller[8].

When the stack is greater than 8, the FORTIFY_SOURCE code notices that the
amount being copied is greater than the source array and complains about
it. It has no idea that the source is pointing to the ring buffer with the
required allocation.

To hide this from the FORTIFY_SOURCE logic, pointer arithmetic is used:

	ptr = ring_buffer_event_data(event);
	entry = ptr;
	ptr += offsetof(typeof(*entry), caller);
	memcpy(ptr, fstack->calls, size);

Link: https://lore.kernel.org/all/20230612160748.4082850-1-svens@linux.ibm.com/
Link: https://lore.kernel.org/linux-trace-kernel/20230712105235.5fc441aa@gandalf.local.home

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Reported-by: Sven Schnelle <svens@linux.ibm.com>
Tested-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-07-12 17:47:49 -04:00
Linus Torvalds
8066178f53 Tracing fixes for 6.5:
- Fix bad git merge of #endif in arm64 code
   A merge of the arm64 tree caused #endif to go into the wrong place
 
 - Fix crash on lseek of write access to tracefs/error_log
   Opening error_log as write only, and then doing an lseek() causes
   a kernel panic, because the lseek() handle expects a "seq_file"
   to exist (which is not done on write only opens). Use tracing_lseek()
   that tests for this instead of calling the default seq lseek handler.
 
 - Check for negative instead of -E2BIG for error on strscpy() returns
   Instead of testing for -E2BIG from strscpy(), to be more robust,
   check for less than zero, which will make sure it catches any error
   that strscpy() may someday return.
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Merge tag 'trace-v6.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing fixes from Steven Rostedt:

 - Fix bad git merge of #endif in arm64 code

   A merge of the arm64 tree caused #endif to go into the wrong place

 - Fix crash on lseek of write access to tracefs/error_log

   Opening error_log as write only, and then doing an lseek() causes a
   kernel panic, because the lseek() handle expects a "seq_file" to
   exist (which is not done on write only opens). Use tracing_lseek()
   that tests for this instead of calling the default seq lseek handler.

 - Check for negative instead of -E2BIG for error on strscpy() returns

   Instead of testing for -E2BIG from strscpy(), to be more robust,
   check for less than zero, which will make sure it catches any error
   that strscpy() may someday return.

* tag 'trace-v6.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing/boot: Test strscpy() against less than zero for error
  arm64: ftrace: fix build error with CONFIG_FUNCTION_GRAPH_TRACER=n
  tracing: Fix null pointer dereference in tracing_err_log_open()
2023-07-06 19:07:15 -07:00
Mateusz Stachyra
02b0095e2f tracing: Fix null pointer dereference in tracing_err_log_open()
Fix an issue in function 'tracing_err_log_open'.
The function doesn't call 'seq_open' if the file is opened only with
write permissions, which results in 'file->private_data' being left as null.
If we then use 'lseek' on that opened file, 'seq_lseek' dereferences
'file->private_data' in 'mutex_lock(&m->lock)', resulting in a kernel panic.
Writing to this node requires root privileges, therefore this bug
has very little security impact.

Tracefs node: /sys/kernel/tracing/error_log

Example Kernel panic:

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000038
Call trace:
 mutex_lock+0x30/0x110
 seq_lseek+0x34/0xb8
 __arm64_sys_lseek+0x6c/0xb8
 invoke_syscall+0x58/0x13c
 el0_svc_common+0xc4/0x10c
 do_el0_svc+0x24/0x98
 el0_svc+0x24/0x88
 el0t_64_sync_handler+0x84/0xe4
 el0t_64_sync+0x1b4/0x1b8
Code: d503201f aa0803e0 aa1f03e1 aa0103e9 (c8e97d02)
---[ end trace 561d1b49c12cf8a5 ]---
Kernel panic - not syncing: Oops: Fatal exception

Link: https://lore.kernel.org/linux-trace-kernel/20230703155237eucms1p4dfb6a19caa14c79eb6c823d127b39024@eucms1p4
Link: https://lore.kernel.org/linux-trace-kernel/20230704102706eucms1p30d7ecdcc287f46ad67679fc8491b2e0f@eucms1p3

Cc: stable@vger.kernel.org
Fixes: 8a062902be ("tracing: Add tracing error log")
Signed-off-by: Mateusz Stachyra <m.stachyra@samsung.com>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-07-05 09:45:45 -04:00
Linus Torvalds
d2a6fd45c5 Probes updates for v6.5:
- fprobe: Pass return address to the fprobe entry/exit callbacks so that
   the callbacks don't need to analyze pt_regs/stack to find the function
   return address.
 
 - kprobe events: cleanup usage of TPARG_FL_FENTRY and TPARG_FL_RETURN
   flags so that those are not set at once.
 
 - fprobe events:
  . Add a new fprobe events for tracing arbitrary function entry and
    exit as a trace event.
  . Add a new tracepoint events for tracing raw tracepoint as a trace
    event. This allows user to trace non user-exposed tracepoints.
  . Move eprobe's event parser code into probe event common file.
  . Introduce BTF (BPF type format) support to kernel probe (kprobe,
    fprobe and tracepoint probe) events so that user can specify traced
    function arguments by name. This also applies the type of argument
    when fetching the argument.
  . Introduce '$arg*' wildcard support if BTF is available. This expands
    the '$arg*' meta argument to all function argument automatically.
  . Check the return value types by BTF. If the function returns 'void',
    '$retval' is rejected.
  . Add some selftest script for fprobe events, tracepoint events and
    BTF support.
  . Update documentation about the fprobe events.
  . Some fixes for above features, document and selftests.
 
 - selftests for ftrace (except for new fprobe events):
  . Add a test case for multiple consecutive probes in a function which
    checks if ftrace based kprobe, optimized kprobe and normal kprobe
    can be defined in the same target function.
  . Add a test case for optimized probe, which checks whether kprobe
    can be optimized or not.
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Merge tag 'probes-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull probes updates from Masami Hiramatsu:

 - fprobe: Pass return address to the fprobe entry/exit callbacks so
   that the callbacks don't need to analyze pt_regs/stack to find the
   function return address.

 - kprobe events: cleanup usage of TPARG_FL_FENTRY and TPARG_FL_RETURN
   flags so that those are not set at once.

 - fprobe events:
      - Add a new fprobe events for tracing arbitrary function entry and
        exit as a trace event.
      - Add a new tracepoint events for tracing raw tracepoint as a
        trace event. This allows user to trace non user-exposed
        tracepoints.
      - Move eprobe's event parser code into probe event common file.
      - Introduce BTF (BPF type format) support to kernel probe (kprobe,
        fprobe and tracepoint probe) events so that user can specify
        traced function arguments by name. This also applies the type of
        argument when fetching the argument.
      - Introduce '$arg*' wildcard support if BTF is available. This
        expands the '$arg*' meta argument to all function argument
        automatically.
      - Check the return value types by BTF. If the function returns
        'void', '$retval' is rejected.
      - Add some selftest script for fprobe events, tracepoint events
        and BTF support.
      - Update documentation about the fprobe events.
      - Some fixes for above features, document and selftests.

 - selftests for ftrace (in addition to the new fprobe events):
      - Add a test case for multiple consecutive probes in a function
        which checks if ftrace based kprobe, optimized kprobe and normal
        kprobe can be defined in the same target function.
      - Add a test case for optimized probe, which checks whether kprobe
        can be optimized or not.

* tag 'probes-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing/probes: Fix tracepoint event with $arg* to fetch correct argument
  Documentation: Fix typo of reference file name
  tracing/probes: Fix to return NULL and keep using current argc
  selftests/ftrace: Add new test case which checks for optimized probes
  selftests/ftrace: Add new test case which adds multiple consecutive probes in a function
  Documentation: tracing/probes: Add fprobe event tracing document
  selftests/ftrace: Add BTF arguments test cases
  selftests/ftrace: Add tracepoint probe test case
  tracing/probes: Add BTF retval type support
  tracing/probes: Add $arg* meta argument for all function args
  tracing/probes: Support function parameters if BTF is available
  tracing/probes: Move event parameter fetching code to common parser
  tracing/probes: Add tracepoint support on fprobe_events
  selftests/ftrace: Add fprobe related testcases
  tracing/probes: Add fprobe events for tracing function entry and exit.
  tracing/probes: Avoid setting TPARG_FL_FENTRY and TPARG_FL_RETURN
  fprobe: Pass return address to the handlers
2023-06-30 10:44:53 -07:00
Linus Torvalds
582c161cf3 hardening updates for v6.5-rc1
- Fix KMSAN vs FORTIFY in strlcpy/strlcat (Alexander Potapenko)
 
 - Convert strreplace() to return string start (Andy Shevchenko)
 
 - Flexible array conversions (Arnd Bergmann, Wyes Karny, Kees Cook)
 
 - Add missing function prototypes seen with W=1 (Arnd Bergmann)
 
 - Fix strscpy() kerndoc typo (Arne Welzel)
 
 - Replace strlcpy() with strscpy() across many subsystems which were
   either Acked by respective maintainers or were trivial changes that
   went ignored for multiple weeks (Azeem Shaikh)
 
 - Remove unneeded cc-option test for UBSAN_TRAP (Nick Desaulniers)
 
 - Add KUnit tests for strcat()-family
 
 - Enable KUnit tests of FORTIFY wrappers under UML
 
 - Add more complete FORTIFY protections for strlcat()
 
 - Add missed disabling of FORTIFY for all arch purgatories.
 
 - Enable -fstrict-flex-arrays=3 globally
 
 - Tightening UBSAN_BOUNDS when using GCC
 
 - Improve checkpatch to check for strcpy, strncpy, and fake flex arrays
 
 - Improve use of const variables in FORTIFY
 
 - Add requested struct_size_t() helper for types not pointers
 
 - Add __counted_by macro for annotating flexible array size members
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Merge tag 'hardening-v6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull hardening updates from Kees Cook:
 "There are three areas of note:

  A bunch of strlcpy()->strscpy() conversions ended up living in my tree
  since they were either Acked by maintainers for me to carry, or got
  ignored for multiple weeks (and were trivial changes).

  The compiler option '-fstrict-flex-arrays=3' has been enabled
  globally, and has been in -next for the entire devel cycle. This
  changes compiler diagnostics (though mainly just -Warray-bounds which
  is disabled) and potential UBSAN_BOUNDS and FORTIFY _warning_
  coverage. In other words, there are no new restrictions, just
  potentially new warnings. Any new FORTIFY warnings we've seen have
  been fixed (usually in their respective subsystem trees). For more
  details, see commit df8fc4e934.

  The under-development compiler attribute __counted_by has been added
  so that we can start annotating flexible array members with their
  associated structure member that tracks the count of flexible array
  elements at run-time. It is possible (likely?) that the exact syntax
  of the attribute will change before it is finalized, but GCC and Clang
  are working together to sort it out. Any changes can be made to the
  macro while we continue to add annotations.

  As an example of that last case, I have a treewide commit waiting with
  such annotations found via Coccinelle:

    https://git.kernel.org/linus/adc5b3cb48a049563dc673f348eab7b6beba8a9b

  Also see commit dd06e72e68 for more details.

  Summary:

   - Fix KMSAN vs FORTIFY in strlcpy/strlcat (Alexander Potapenko)

   - Convert strreplace() to return string start (Andy Shevchenko)

   - Flexible array conversions (Arnd Bergmann, Wyes Karny, Kees Cook)

   - Add missing function prototypes seen with W=1 (Arnd Bergmann)

   - Fix strscpy() kerndoc typo (Arne Welzel)

   - Replace strlcpy() with strscpy() across many subsystems which were
     either Acked by respective maintainers or were trivial changes that
     went ignored for multiple weeks (Azeem Shaikh)

   - Remove unneeded cc-option test for UBSAN_TRAP (Nick Desaulniers)

   - Add KUnit tests for strcat()-family

   - Enable KUnit tests of FORTIFY wrappers under UML

   - Add more complete FORTIFY protections for strlcat()

   - Add missed disabling of FORTIFY for all arch purgatories.

   - Enable -fstrict-flex-arrays=3 globally

   - Tightening UBSAN_BOUNDS when using GCC

   - Improve checkpatch to check for strcpy, strncpy, and fake flex
     arrays

   - Improve use of const variables in FORTIFY

   - Add requested struct_size_t() helper for types not pointers

   - Add __counted_by macro for annotating flexible array size members"

* tag 'hardening-v6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (54 commits)
  netfilter: ipset: Replace strlcpy with strscpy
  uml: Replace strlcpy with strscpy
  um: Use HOST_DIR for mrproper
  kallsyms: Replace all non-returning strlcpy with strscpy
  sh: Replace all non-returning strlcpy with strscpy
  of/flattree: Replace all non-returning strlcpy with strscpy
  sparc64: Replace all non-returning strlcpy with strscpy
  Hexagon: Replace all non-returning strlcpy with strscpy
  kobject: Use return value of strreplace()
  lib/string_helpers: Change returned value of the strreplace()
  jbd2: Avoid printing outside the boundary of the buffer
  checkpatch: Check for 0-length and 1-element arrays
  riscv/purgatory: Do not use fortified string functions
  s390/purgatory: Do not use fortified string functions
  x86/purgatory: Do not use fortified string functions
  acpi: Replace struct acpi_table_slit 1-element array with flex-array
  clocksource: Replace all non-returning strlcpy with strscpy
  string: use __builtin_memcpy() in strlcpy/strlcat
  staging: most: Replace all non-returning strlcpy with strscpy
  drm/i2c: tda998x: Replace all non-returning strlcpy with strscpy
  ...
2023-06-27 21:24:18 -07:00
Linus Torvalds
3eccc0c886 for-6.5/splice-2023-06-23
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Merge tag 'for-6.5/splice-2023-06-23' of git://git.kernel.dk/linux

Pull splice updates from Jens Axboe:
 "This kills off ITER_PIPE to avoid a race between truncate,
  iov_iter_revert() on the pipe and an as-yet incomplete DMA to a bio
  with unpinned/unref'ed pages from an O_DIRECT splice read. This causes
  memory corruption.

  Instead, we either use (a) filemap_splice_read(), which invokes the
  buffered file reading code and splices from the pagecache into the
  pipe; (b) copy_splice_read(), which bulk-allocates a buffer, reads
  into it and then pushes the filled pages into the pipe; or (c) handle
  it in filesystem-specific code.

  Summary:

   - Rename direct_splice_read() to copy_splice_read()

   - Simplify the calculations for the number of pages to be reclaimed
     in copy_splice_read()

   - Turn do_splice_to() into a helper, vfs_splice_read(), so that it
     can be used by overlayfs and coda to perform the checks on the
     lower fs

   - Make vfs_splice_read() jump to copy_splice_read() to handle
     direct-I/O and DAX

   - Provide shmem with its own splice_read to handle non-existent pages
     in the pagecache. We don't want a ->read_folio() as we don't want
     to populate holes, but filemap_get_pages() requires it

   - Provide overlayfs with its own splice_read to call down to a lower
     layer as overlayfs doesn't provide ->read_folio()

   - Provide coda with its own splice_read to call down to a lower layer
     as coda doesn't provide ->read_folio()

   - Direct ->splice_read to copy_splice_read() in tty, procfs, kernfs
     and random files as they just copy to the output buffer and don't
     splice pages

   - Provide wrappers for afs, ceph, ecryptfs, ext4, f2fs, nfs, ntfs3,
     ocfs2, orangefs, xfs and zonefs to do locking and/or revalidation

   - Make cifs use filemap_splice_read()

   - Replace pointers to generic_file_splice_read() with pointers to
     filemap_splice_read() as DIO and DAX are handled in the caller;
     filesystems can still provide their own alternate ->splice_read()
     op

   - Remove generic_file_splice_read()

   - Remove ITER_PIPE and its paraphernalia as generic_file_splice_read
     was the only user"

* tag 'for-6.5/splice-2023-06-23' of git://git.kernel.dk/linux: (31 commits)
  splice: kdoc for filemap_splice_read() and copy_splice_read()
  iov_iter: Kill ITER_PIPE
  splice: Remove generic_file_splice_read()
  splice: Use filemap_splice_read() instead of generic_file_splice_read()
  cifs: Use filemap_splice_read()
  trace: Convert trace/seq to use copy_splice_read()
  zonefs: Provide a splice-read wrapper
  xfs: Provide a splice-read wrapper
  orangefs: Provide a splice-read wrapper
  ocfs2: Provide a splice-read wrapper
  ntfs3: Provide a splice-read wrapper
  nfs: Provide a splice-read wrapper
  f2fs: Provide a splice-read wrapper
  ext4: Provide a splice-read wrapper
  ecryptfs: Provide a splice-read wrapper
  ceph: Provide a splice-read wrapper
  afs: Provide a splice-read wrapper
  9p: Add splice_read wrapper
  net: Make sock_splice_read() use copy_splice_read() by default
  tty, proc, kernfs, random: Use copy_splice_read()
  ...
2023-06-26 11:52:12 -07:00
Masami Hiramatsu (Google)
b576e09701 tracing/probes: Support function parameters if BTF is available
Support function or tracepoint parameters by name if BTF support is enabled
and the event is for function entry (this feature can be used with kprobe-
events, fprobe-events and tracepoint probe events.)

Note that the BTF variable syntax does not require a prefix. If it starts
with an alphabetic character or an underscore ('_') without a prefix like
'$' and '%', it is considered as a BTF variable.
If you specify only the BTF variable name, the argument name will also
be the same name instead of 'arg*'.

 # echo 'p vfs_read count pos' >> dynamic_events
 # echo 'f vfs_write count pos' >> dynamic_events
 # echo 't sched_overutilized_tp rd overutilized' >> dynamic_events
 # cat dynamic_events
p:kprobes/p_vfs_read_0 vfs_read count=count pos=pos
f:fprobes/vfs_write__entry vfs_write count=count pos=pos
t:tracepoints/sched_overutilized_tp sched_overutilized_tp rd=rd overutilized=overutilized

Link: https://lore.kernel.org/all/168507474014.913472.16963996883278039183.stgit@mhiramat.roam.corp.google.com/

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
2023-06-06 21:39:56 +09:00
Masami Hiramatsu (Google)
e2d0d7b2f4 tracing/probes: Add tracepoint support on fprobe_events
Allow fprobe_events to trace raw tracepoints so that user can trace
tracepoints which don't have traceevent wrappers. This new event is
always available if the fprobe_events is enabled (thus no kconfig),
because the fprobe_events depends on the trace-event and traceporint.

e.g.
 # echo 't sched_overutilized_tp' >> dynamic_events
 # echo 't 9p_client_req' >> dynamic_events
 # cat dynamic_events
t:tracepoints/sched_overutilized_tp sched_overutilized_tp
t:tracepoints/_9p_client_req 9p_client_req

The event name is based on the tracepoint name, but if it is started
with digit character, an underscore '_' will be added.

NOTE: to avoid further confusion, this renames TPARG_FL_TPOINT to
TPARG_FL_TEVENT because this flag is used for eprobe (trace-event probe).
And reuse TPARG_FL_TPOINT for this raw tracepoint probe.

Link: https://lore.kernel.org/all/168507471874.913472.17214624519622959593.stgit@mhiramat.roam.corp.google.com/

Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202305020453.afTJ3VVp-lkp@intel.com/
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2023-06-06 21:39:55 +09:00
Masami Hiramatsu (Google)
334e5519c3 tracing/probes: Add fprobe events for tracing function entry and exit.
Add fprobe events for tracing function entry and exit instead of kprobe
events. With this change, we can continue to trace function entry/exit
even if the CONFIG_KPROBES_ON_FTRACE is not available. Since
CONFIG_KPROBES_ON_FTRACE requires the CONFIG_DYNAMIC_FTRACE_WITH_REGS,
it is not available if the architecture only supports
CONFIG_DYNAMIC_FTRACE_WITH_ARGS. And that means kprobe events can not
probe function entry/exit effectively on such architecture.
But this can be solved if the dynamic events supports fprobe events.

The fprobe event is a new dynamic events which is only for the function
(symbol) entry and exit. This event accepts non register fetch arguments
so that user can trace the function arguments and return values.

The fprobe events syntax is here;

 f[:[GRP/][EVENT]] FUNCTION [FETCHARGS]
 f[MAXACTIVE][:[GRP/][EVENT]] FUNCTION%return [FETCHARGS]

E.g.

 # echo 'f vfs_read $arg1'  >> dynamic_events
 # echo 'f vfs_read%return $retval'  >> dynamic_events
 # cat dynamic_events
 f:fprobes/vfs_read__entry vfs_read arg1=$arg1
 f:fprobes/vfs_read__exit vfs_read%return arg1=$retval
 # echo 1 > events/fprobes/enable
 # head -n 20 trace | tail
 #           TASK-PID     CPU#  |||||  TIMESTAMP  FUNCTION
 #              | |         |   |||||     |         |
              sh-142     [005] ...1.   448.386420: vfs_read__entry: (vfs_read+0x4/0x340) arg1=0xffff888007f7c540
              sh-142     [005] .....   448.386436: vfs_read__exit: (ksys_read+0x75/0x100 <- vfs_read) arg1=0x1
              sh-142     [005] ...1.   448.386451: vfs_read__entry: (vfs_read+0x4/0x340) arg1=0xffff888007f7c540
              sh-142     [005] .....   448.386458: vfs_read__exit: (ksys_read+0x75/0x100 <- vfs_read) arg1=0x1
              sh-142     [005] ...1.   448.386469: vfs_read__entry: (vfs_read+0x4/0x340) arg1=0xffff888007f7c540
              sh-142     [005] .....   448.386476: vfs_read__exit: (ksys_read+0x75/0x100 <- vfs_read) arg1=0x1
              sh-142     [005] ...1.   448.602073: vfs_read__entry: (vfs_read+0x4/0x340) arg1=0xffff888007f7c540
              sh-142     [005] .....   448.602089: vfs_read__exit: (ksys_read+0x75/0x100 <- vfs_read) arg1=0x1

Link: https://lore.kernel.org/all/168507469754.913472.6112857614708350210.stgit@mhiramat.roam.corp.google.com/

Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/all/202302011530.7vm4O8Ro-lkp@intel.com/
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2023-06-06 21:39:55 +09:00
Steven Rostedt (Google)
ac9d2cb1d5 tracing: Only make selftest conditionals affect the global_trace
The tracing_selftest_running and tracing_selftest_disabled variables were
to keep trace_printk() and other writes from affecting the tracing
selftests, as the tracing selftests would examine the ring buffer to see
if it contained what it expected or not. trace_printk() and friends could
add to the ring buffer and cause the selftests to fail (and then disable
the tracer that was being tested). To keep that from happening, these
variables were added and would keep trace_printk() and friends from
writing to the ring buffer while the tests were going on.

But this was only the top level ring buffer (owned by the global_trace
instance). There is no reason to prevent writing into ring buffers of
other instances via the trace_array_printk() and friends. For the
functions that could be used by other instances, check if the global_trace
is the tracer instance that is being written to before deciding to not
allow the write.

Link: https://lkml.kernel.org/r/20230528051742.1325503-5-rostedt@goodmis.org

Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-05-28 21:15:33 -04:00
Steven Rostedt (Google)
a3ae76d7ff tracing: Make tracing_selftest_running/delete nops when not used
There's no reason to test the condition variables tracing_selftest_running
or tracing_selftest_delete when tracing selftests are not enabled. Make
them define 0s when not the selftests are not configured in.

Link: https://lkml.kernel.org/r/20230528051742.1325503-4-rostedt@goodmis.org

Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-05-28 21:15:26 -04:00
Steven Rostedt (Google)
9da705d432 tracing: Have tracer selftests call cond_resched() before running
As there are more and more internal selftests being added to the Linux
kernel (KSAN, lockdep, etc) the selftests are taking longer to run when
these are enabled. Add a cond_resched() to the calling of
do_run_tracer_selftest() to force a schedule if NEED_RESCHED is set,
otherwise the soft lockup watchdog may trigger on boot up.

Link: https://lkml.kernel.org/r/20230528051742.1325503-3-rostedt@goodmis.org

Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-05-28 21:15:17 -04:00
Steven Rostedt (Google)
e8352cf577 tracing: Move setting of tracing_selftest_running out of register_tracer()
The variables tracing_selftest_running and tracing_selftest_disabled are
only used for when CONFIG_FTRACE_STARTUP_TEST is enabled. Make them only
visible within the selftest code. The setting of those variables are in
the register_tracer() call, and set in a location where they do not need
to be. Create a wrapper around run_tracer_selftest() called
do_run_tracer_selftest() which sets those variables, and have
register_tracer() call that instead.

Having those variables only set within the CONFIG_FTRACE_STARTUP_TEST
scope gets rid of them (and also the ability to remove testing against
them) when the startup tests are not enabled (most cases).

Link: https://lkml.kernel.org/r/20230528051742.1325503-2-rostedt@goodmis.org

Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-05-28 21:15:04 -04:00
Azeem Shaikh
c7dce4c5d9 tracing: Replace all non-returning strlcpy with strscpy
strlcpy() reads the entire source buffer first.
This read may exceed the destination size limit.
This is both inefficient and can lead to linear read
overflows if a source string is not NUL-terminated [1].
In an effort to remove strlcpy() completely [2], replace
strlcpy() here with strscpy().

No return values were used, so direct replacement with strlcpy is safe.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89

Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230516143956.1367827-1-azeemshaikh38@gmail.com
2023-05-26 13:52:19 -07:00
David Howells
5bd4990f19 trace: Convert trace/seq to use copy_splice_read()
For the splice from the trace seq buffer, just use copy_splice_read().

In the future, something better can probably be done by gifting pages from
seq->buf into the pipe, but that would require changing seq->buf into a
vmap over an array of pages.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Christoph Hellwig <hch@lst.de>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: Jens Axboe <axboe@kernel.dk>
cc: Steven Rostedt <rostedt@goodmis.org>
cc: Masami Hiramatsu <mhiramat@kernel.org>
cc: linux-kernel@vger.kernel.org
cc: linux-trace-kernel@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-block@vger.kernel.org
cc: linux-mm@kvack.org
Link: https://lore.kernel.org/r/20230522135018.2742245-27-dhowells@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-05-24 08:42:16 -06:00
Steven Rostedt (Google)
4b512860bd tracing: Rename stacktrace field to common_stacktrace
The histogram and synthetic events can use a pseudo event called
"stacktrace" that will create a stacktrace at the time of the event and
use it just like it was a normal field. We have other pseudo events such
as "common_cpu" and "common_timestamp". To stay consistent with that,
convert "stacktrace" to "common_stacktrace". As this was used in older
kernels, to keep backward compatibility, this will act just like
"common_cpu" did with "cpu". That is, "cpu" will be the same as
"common_cpu" unless the event has a "cpu" field. In which case, the
event's field is used. The same is true with "stacktrace".

Also update the documentation to reflect this change.

Link: https://lore.kernel.org/linux-trace-kernel/20230523230913.6860e28d@rorschach.local.home

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-05-23 23:38:23 -04:00
Linus Torvalds
e919a3f705 Minor tracing updates:
- Make buffer_percent read/write. The buffer_percent file is how users can
   state how long to block on the tracing buffer depending on how much
   is in the buffer. When it hits the "buffer_percent" it will wake the
   task waiting on the buffer. For some reason it was set to read-only.
   This was not noticed because testing was done as root without SELinux,
   but with SELinux it will prevent even root to write to it without having
   CAP_DAC_OVERRIDE.
 
 - The "touched_functions" was added this merge window, but one of the
   reasons for adding it was not implemented. That was to show what functions
   were not only touched, but had either a direct trampoline attached to
   it, or a kprobe or live kernel patching that can "hijack" the function
   to run a different function. The point is to know if there's functions
   in the kernel that may not be behaving as the kernel code shows. This can
   be used for debugging. TODO: Add this information to kernel oops too.
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Merge tag 'trace-v6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull more tracing updates from Steven Rostedt:

 - Make buffer_percent read/write.

   The buffer_percent file is how users can state how long to block on
   the tracing buffer depending on how much is in the buffer. When it
   hits the "buffer_percent" it will wake the task waiting on the
   buffer. For some reason it was set to read-only.

   This was not noticed because testing was done as root without
   SELinux, but with SELinux it will prevent even root to write to it
   without having CAP_DAC_OVERRIDE.

 - The "touched_functions" was added this merge window, but one of the
   reasons for adding it was not implemented.

   That was to show what functions were not only touched, but had either
   a direct trampoline attached to it, or a kprobe or live kernel
   patching that can "hijack" the function to run a different function.
   The point is to know if there's functions in the kernel that may not
   be behaving as the kernel code shows. This can be used for debugging.

   TODO: Add this information to kernel oops too.

* tag 'trace-v6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ftrace: Add MODIFIED flag to show if IPMODIFY or direct was attached
  tracing: Fix permissions for the buffer_percent file
2023-05-05 13:11:02 -07:00
Ondrej Mosnacek
4f94559f40 tracing: Fix permissions for the buffer_percent file
This file defines both read and write operations, yet it is being
created as read-only. This means that it can't be written to without the
CAP_DAC_OVERRIDE capability. Fix the permissions to allow root to write
to it without the need to override DAC perms.

Link: https://lore.kernel.org/linux-trace-kernel/20230503140114.3280002-1-omosnace@redhat.com

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Fixes: 03329f9939 ("tracing: Add tracefs file buffer_percentage")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-05-03 12:45:00 -04:00
Linus Torvalds
d579c468d7 tracing updates for 6.4:
- User events are finally ready!
   After lots of collaboration between various parties, we finally locked
   down on a stable interface for user events that can also work with user
   space only tracing. This is implemented by telling the kernel (or user
   space library, but that part is user space only and not part of this
   patch set), where the variable is that the application uses to know if
   something is listening to the trace. There's also an interface to tell
   the kernel about these events, which will show up in the
   /sys/kernel/tracing/events/user_events/ directory, where it can be
    enabled. When it's enabled, the kernel will update the variable, to tell
   the application to start writing to the kernel.
   See https://lwn.net/Articles/927595/
 
 - Cleaned up the direct trampolines code to simplify arm64 addition of
   direct trampolines. Direct trampolines use the ftrace interface but
   instead of jumping to the ftrace trampoline, applications (mostly BPF)
   can register their own trampoline for performance reasons.
 
 - Some updates to the fprobe infrastructure. fprobes are more efficient than
   kprobes, as it does not need to save all the registers that kprobes on
   ftrace do. More work needs to be done before the fprobes will be exposed
   as dynamic events.
 
 - More updates to references to the obsolete path of
   /sys/kernel/debug/tracing for the new /sys/kernel/tracing path.
 
 - Add a seq_buf_do_printk() helper to seq_bufs, to print a large buffer line
   by line instead of all at once. There's users in production kernels that
   have a large data dump that originally used printk() directly, but the
   data dump was larger than what printk() allowed as a single print.
   Using seq_buf() to do the printing fixes that.
 
 - Add /sys/kernel/tracing/touched_functions that shows all functions that
   was every traced by ftrace or a direct trampoline. This is used for
   debugging issues where a traced function could have caused a crash by
   a bpf program or live patching.
 
 - Add a "fields" option that is similar to "raw" but outputs the fields of
   the events. It's easier to read by humans.
 
 - Some minor fixes and clean ups.
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Merge tag 'trace-v6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt:

 - User events are finally ready!

   After lots of collaboration between various parties, we finally
   locked down on a stable interface for user events that can also work
   with user space only tracing.

   This is implemented by telling the kernel (or user space library, but
   that part is user space only and not part of this patch set), where
   the variable is that the application uses to know if something is
   listening to the trace.

   There's also an interface to tell the kernel about these events,
   which will show up in the /sys/kernel/tracing/events/user_events/
   directory, where it can be enabled.

   When it's enabled, the kernel will update the variable, to tell the
   application to start writing to the kernel.

   See https://lwn.net/Articles/927595/

 - Cleaned up the direct trampolines code to simplify arm64 addition of
   direct trampolines.

   Direct trampolines use the ftrace interface but instead of jumping to
   the ftrace trampoline, applications (mostly BPF) can register their
   own trampoline for performance reasons.

 - Some updates to the fprobe infrastructure. fprobes are more efficient
   than kprobes, as it does not need to save all the registers that
   kprobes on ftrace do. More work needs to be done before the fprobes
   will be exposed as dynamic events.

 - More updates to references to the obsolete path of
   /sys/kernel/debug/tracing for the new /sys/kernel/tracing path.

 - Add a seq_buf_do_printk() helper to seq_bufs, to print a large buffer
   line by line instead of all at once.

   There are users in production kernels that have a large data dump
   that originally used printk() directly, but the data dump was larger
   than what printk() allowed as a single print.

   Using seq_buf() to do the printing fixes that.

 - Add /sys/kernel/tracing/touched_functions that shows all functions
   that was every traced by ftrace or a direct trampoline. This is used
   for debugging issues where a traced function could have caused a
   crash by a bpf program or live patching.

 - Add a "fields" option that is similar to "raw" but outputs the fields
   of the events. It's easier to read by humans.

 - Some minor fixes and clean ups.

* tag 'trace-v6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (41 commits)
  ring-buffer: Sync IRQ works before buffer destruction
  tracing: Add missing spaces in trace_print_hex_seq()
  ring-buffer: Ensure proper resetting of atomic variables in ring_buffer_reset_online_cpus
  recordmcount: Fix memory leaks in the uwrite function
  tracing/user_events: Limit max fault-in attempts
  tracing/user_events: Prevent same address and bit per process
  tracing/user_events: Ensure bit is cleared on unregister
  tracing/user_events: Ensure write index cannot be negative
  seq_buf: Add seq_buf_do_printk() helper
  tracing: Fix print_fields() for __dyn_loc/__rel_loc
  tracing/user_events: Set event filter_type from type
  ring-buffer: Clearly check null ptr returned by rb_set_head_page()
  tracing: Unbreak user events
  tracing/user_events: Use print_format_fields() for trace output
  tracing/user_events: Align structs with tabs for readability
  tracing/user_events: Limit global user_event count
  tracing/user_events: Charge event allocs to cgroups
  tracing/user_events: Update documentation for ABI
  tracing/user_events: Use write ABI in example
  tracing/user_events: Add ABI self-test
  ...
2023-04-28 15:57:53 -07:00
Steven Rostedt (Google)
3357c6e429 tracing: Free error logs of tracing instances
When a tracing instance is removed, the error messages that hold errors
that occurred in the instance needs to be freed. The following reports a
memory leak:

 # cd /sys/kernel/tracing
 # mkdir instances/foo
 # echo 'hist:keys=x' > instances/foo/events/sched/sched_switch/trigger
 # cat instances/foo/error_log
 [  117.404795] hist:sched:sched_switch: error: Couldn't find field
   Command: hist:keys=x
                      ^
 # rmdir instances/foo

Then check for memory leaks:

 # echo scan > /sys/kernel/debug/kmemleak
 # cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff88810d8ec700 (size 192):
  comm "bash", pid 869, jiffies 4294950577 (age 215.752s)
  hex dump (first 32 bytes):
    60 dd 68 61 81 88 ff ff 60 dd 68 61 81 88 ff ff  `.ha....`.ha....
    a0 30 8c 83 ff ff ff ff 26 00 0a 00 00 00 00 00  .0......&.......
  backtrace:
    [<00000000dae26536>] kmalloc_trace+0x2a/0xa0
    [<00000000b2938940>] tracing_log_err+0x277/0x2e0
    [<000000004a0e1b07>] parse_atom+0x966/0xb40
    [<0000000023b24337>] parse_expr+0x5f3/0xdb0
    [<00000000594ad074>] event_hist_trigger_parse+0x27f8/0x3560
    [<00000000293a9645>] trigger_process_regex+0x135/0x1a0
    [<000000005c22b4f2>] event_trigger_write+0x87/0xf0
    [<000000002cadc509>] vfs_write+0x162/0x670
    [<0000000059c3b9be>] ksys_write+0xca/0x170
    [<00000000f1cddc00>] do_syscall_64+0x3e/0xc0
    [<00000000868ac68c>] entry_SYSCALL_64_after_hwframe+0x72/0xdc
unreferenced object 0xffff888170c35a00 (size 32):
  comm "bash", pid 869, jiffies 4294950577 (age 215.752s)
  hex dump (first 32 bytes):
    0a 20 20 43 6f 6d 6d 61 6e 64 3a 20 68 69 73 74  .  Command: hist
    3a 6b 65 79 73 3d 78 0a 00 00 00 00 00 00 00 00  :keys=x.........
  backtrace:
    [<000000006a747de5>] __kmalloc+0x4d/0x160
    [<000000000039df5f>] tracing_log_err+0x29b/0x2e0
    [<000000004a0e1b07>] parse_atom+0x966/0xb40
    [<0000000023b24337>] parse_expr+0x5f3/0xdb0
    [<00000000594ad074>] event_hist_trigger_parse+0x27f8/0x3560
    [<00000000293a9645>] trigger_process_regex+0x135/0x1a0
    [<000000005c22b4f2>] event_trigger_write+0x87/0xf0
    [<000000002cadc509>] vfs_write+0x162/0x670
    [<0000000059c3b9be>] ksys_write+0xca/0x170
    [<00000000f1cddc00>] do_syscall_64+0x3e/0xc0
    [<00000000868ac68c>] entry_SYSCALL_64_after_hwframe+0x72/0xdc

The problem is that the error log needs to be freed when the instance is
removed.

Link: https://lore.kernel.org/lkml/76134d9f-a5ba-6a0d-37b3-28310b4a1e91@alu.unizg.hr/
Link: https://lore.kernel.org/linux-trace-kernel/20230404194504.5790b95f@gandalf.local.home

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Thorsten Leemhuis <regressions@leemhuis.info>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Eric Biggers <ebiggers@kernel.org>
Fixes: 2f754e771b ("tracing: Have the error logs show up in the proper instances")
Reported-by: Mirsad Goran Todorovac <mirsad.todorovac@alu.unizg.hr>
Tested-by: Mirsad Todorovac <mirsad.todorovac@alu.unizg.hr>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-04-05 09:54:37 -04:00
Steven Rostedt (Google)
e94891641c tracing: Fix ftrace_boot_snapshot command line logic
The kernel command line ftrace_boot_snapshot by itself is supposed to
trigger a snapshot at the end of boot up of the main top level trace
buffer. A ftrace_boot_snapshot=foo will do the same for an instance called
foo that was created by trace_instance=foo,...

The logic was broken where if ftrace_boot_snapshot was by itself, it would
trigger a snapshot for all instances that had tracing enabled, regardless
if it asked for a snapshot or not.

When a snapshot is requested for a buffer, the buffer's
tr->allocated_snapshot is set to true. Use that to know if a trace buffer
wants a snapshot at boot up or not.

Since the top level buffer is part of the ftrace_trace_arrays list,
there's no reason to treat it differently than the other buffers. Just
iterate the list if ftrace_boot_snapshot was specified.

Link: https://lkml.kernel.org/r/20230405022341.895334039@goodmis.org

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ross Zwisler <zwisler@google.com>
Fixes: 9c1c251d67 ("tracing: Allow boot instances to have snapshot buffers")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-04-04 22:29:53 -04:00
Steven Rostedt (Google)
9d52727f80 tracing: Have tracing_snapshot_instance_cond() write errors to the appropriate instance
If a trace instance has a failure with its snapshot code, the error
message is to be written to that instance's buffer. But currently, the
message is written to the top level buffer. Worse yet, it may also disable
the top level buffer and not the instance that had the issue.

Link: https://lkml.kernel.org/r/20230405022341.688730321@goodmis.org

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ross Zwisler <zwisler@google.com>
Fixes: 2824f50332 ("tracing: Make the snapshot trigger work with instances")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-04-04 22:29:53 -04:00
Steven Rostedt (Google)
80a76994b2 tracing: Add "fields" option to show raw trace event fields
The hex, raw and bin formats come from the old PREEMPT_RT patch set
latency tracer. That actually gave real alternatives to reading the ascii
buffer. But they have started to bit rot and they do not give a good
representation of the tracing data.

Add "fields" option that will read the trace event fields and parse the
data from how the fields are defined:

With "fields" = 0 (default)

 echo 1 > events/sched/sched_switch/enable
 cat trace
         <idle>-0       [003] d..2.   540.078653: sched_switch: prev_comm=swapper/3 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=kworker/3:1 next_pid=83 next_prio=120
     kworker/3:1-83      [003] d..2.   540.078860: sched_switch: prev_comm=kworker/3:1 prev_pid=83 prev_prio=120 prev_state=I ==> next_comm=swapper/3 next_pid=0 next_prio=120
          <idle>-0       [003] d..2.   540.206423: sched_switch: prev_comm=swapper/3 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=sshd next_pid=807 next_prio=120
            sshd-807     [003] d..2.   540.206531: sched_switch: prev_comm=sshd prev_pid=807 prev_prio=120 prev_state=S ==> next_comm=swapper/3 next_pid=0 next_prio=120
          <idle>-0       [001] d..2.   540.206597: sched_switch: prev_comm=swapper/1 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=kworker/u16:4 next_pid=58 next_prio=120
   kworker/u16:4-58      [001] d..2.   540.206617: sched_switch: prev_comm=kworker/u16:4 prev_pid=58 prev_prio=120 prev_state=I ==> next_comm=bash next_pid=830 next_prio=120
            bash-830     [001] d..2.   540.206678: sched_switch: prev_comm=bash prev_pid=830 prev_prio=120 prev_state=R ==> next_comm=kworker/u16:4 next_pid=58 next_prio=120
   kworker/u16:4-58      [001] d..2.   540.206696: sched_switch: prev_comm=kworker/u16:4 prev_pid=58 prev_prio=120 prev_state=I ==> next_comm=bash next_pid=830 next_prio=120
            bash-830     [001] d..2.   540.206713: sched_switch: prev_comm=bash prev_pid=830 prev_prio=120 prev_state=R ==> next_comm=kworker/u16:4 next_pid=58 next_prio=120

 echo 1 > options/fields
           <...>-998     [002] d..2.   538.643732: sched_switch: next_prio=0x78 (120) next_pid=0x0 (0) next_comm=swapper/2 prev_state=0x20 (32) prev_prio=0x78 (120) prev_pid=0x3e6 (998) prev_comm=trace-cmd
          <idle>-0       [001] d..2.   538.643806: sched_switch: next_prio=0x78 (120) next_pid=0x33e (830) next_comm=bash prev_state=0x0 (0) prev_prio=0x78 (120) prev_pid=0x0 (0) prev_comm=swapper/1
            bash-830     [001] d..2.   538.644106: sched_switch: next_prio=0x78 (120) next_pid=0x3a (58) next_comm=kworker/u16:4 prev_state=0x0 (0) prev_prio=0x78 (120) prev_pid=0x33e (830) prev_comm=bash
   kworker/u16:4-58      [001] d..2.   538.644130: sched_switch: next_prio=0x78 (120) next_pid=0x33e (830) next_comm=bash prev_state=0x80 (128) prev_prio=0x78 (120) prev_pid=0x3a (58) prev_comm=kworker/u16:4
            bash-830     [001] d..2.   538.644180: sched_switch: next_prio=0x78 (120) next_pid=0x3a (58) next_comm=kworker/u16:4 prev_state=0x0 (0) prev_prio=0x78 (120) prev_pid=0x33e (830) prev_comm=bash
   kworker/u16:4-58      [001] d..2.   538.644185: sched_switch: next_prio=0x78 (120) next_pid=0x33e (830) next_comm=bash prev_state=0x80 (128) prev_prio=0x78 (120) prev_pid=0x3a (58) prev_comm=kworker/u16:4
            bash-830     [001] d..2.   538.644204: sched_switch: next_prio=0x78 (120) next_pid=0x0 (0) next_comm=swapper/1 prev_state=0x1 (1) prev_prio=0x78 (120) prev_pid=0x33e (830) prev_comm=bash
          <idle>-0       [003] d..2.   538.644211: sched_switch: next_prio=0x78 (120) next_pid=0x327 (807) next_comm=sshd prev_state=0x0 (0) prev_prio=0x78 (120) prev_pid=0x0 (0) prev_comm=swapper/3
            sshd-807     [003] d..2.   538.644340: sched_switch: next_prio=0x78 (120) next_pid=0x0 (0) next_comm=swapper/3 prev_state=0x1 (1) prev_prio=0x78 (120) prev_pid=0x327 (807) prev_comm=sshd

It traces the data safely without using the trace print formatting.

Link: https://lore.kernel.org/linux-trace-kernel/20230328145156.497651be@gandalf.local.home

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-03-29 06:52:08 -04:00
Linus Torvalds
eaba52d63b Tracing fixes for 6.3:
- Fix setting affinity of hwlat threads in containers
   Using sched_set_affinity() has unwanted side effects when being
   called within a container. Use set_cpus_allowed_ptr() instead.
 
 - Fix per cpu thread management of the hwlat tracer
   * Do not start per_cpu threads if one is already running for the CPU.
   * When starting per_cpu threads, do not clear the kthread variable
     as it may already be set to running per cpu threads
 
 - Fix return value for test_gen_kprobe_cmd()
   On error the return value was overwritten by being set to
   the result of the call from kprobe_event_delete(), which would
   likely succeed, and thus have the function return success.
 
 - Fix splice() reads from the trace file that was broken by
   36e2c7421f ("fs: don't allow splice read/write without explicit ops")
 
 - Remove obsolete and confusing comment in ring_buffer.c
   The original design of the ring buffer used struct page flags
   for tricks to optimize, which was shortly removed due to them
   being tricks. But a comment for those tricks remained.
 
 - Set local functions and variables to static
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Merge tag 'trace-v6.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing fixes from Steven Rostedt:

 - Fix setting affinity of hwlat threads in containers

   Using sched_set_affinity() has unwanted side effects when being
   called within a container. Use set_cpus_allowed_ptr() instead

 - Fix per cpu thread management of the hwlat tracer:
    - Do not start per_cpu threads if one is already running for the CPU
    - When starting per_cpu threads, do not clear the kthread variable
      as it may already be set to running per cpu threads

 - Fix return value for test_gen_kprobe_cmd()

   On error the return value was overwritten by being set to the result
   of the call from kprobe_event_delete(), which would likely succeed,
   and thus have the function return success

 - Fix splice() reads from the trace file that was broken by commit
   36e2c7421f ("fs: don't allow splice read/write without explicit
   ops")

 - Remove obsolete and confusing comment in ring_buffer.c

   The original design of the ring buffer used struct page flags for
   tricks to optimize, which was shortly removed due to them being
   tricks. But a comment for those tricks remained

 - Set local functions and variables to static

* tag 'trace-v6.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing/hwlat: Replace sched_setaffinity with set_cpus_allowed_ptr
  ring-buffer: remove obsolete comment for free_buffer_page()
  tracing: Make splice_read available again
  ftrace: Set direct_ops storage-class-specifier to static
  trace/hwlat: Do not start per-cpu thread if it is already running
  trace/hwlat: Do not wipe the contents of per-cpu thread data
  tracing/osnoise: set several trace_osnoise.c variables storage-class-specifier to static
  tracing: Fix wrong return in kprobe_event_gen_test.c
2023-03-19 10:46:02 -07:00
Sung-hun Kim
e400be674a tracing: Make splice_read available again
Since the commit 36e2c7421f ("fs: don't allow splice read/write
without explicit ops") is applied to the kernel, splice() and
sendfile() calls on the trace file (/sys/kernel/debug/tracing
/trace) return EINVAL.

This patch restores these system calls by initializing splice_read
in file_operations of the trace file. This patch only enables such
functionalities for the read case.

Link: https://lore.kernel.org/linux-trace-kernel/20230314013707.28814-1-sfoon.kim@samsung.com

Cc: stable@vger.kernel.org
Fixes: 36e2c7421f ("fs: don't allow splice read/write without explicit ops")
Signed-off-by: Sung-hun Kim <sfoon.kim@samsung.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-03-19 13:16:21 -04:00
Linus Torvalds
2b79eb73e2 probes updates for 6.3:
- Skip negative return code check for snprintf in eprobe.
 
 - Add recursive call test cases for kprobe unit test
 
 - Add 'char' type to probe events to show it as the character instead of value.
 
 - Update kselftest kprobe-event testcase to ignore '__pfx_' symbols.
 
 - Fix kselftest to check filter on eprobe event correctly.
 
 - Add filter on eprobe to the README file in tracefs.
 
 - Fix optprobes to check whether there is 'under unoptimizing' optprobe when optimizing another kprobe correctly.
 
 - Fix optprobe to check whether there is 'under unoptimizing' optprobe when fetching the original instruction correctly.
 
 - Fix optprobe to free 'forcibly unoptimized' optprobe correctly.
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Merge tag 'probes-v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull kprobes updates from Masami Hiramatsu:

 - Skip negative return code check for snprintf in eprobe

 - Add recursive call test cases for kprobe unit test

 - Add 'char' type to probe events to show it as the character instead
   of value

 - Update kselftest kprobe-event testcase to ignore '__pfx_' symbols

 - Fix kselftest to check filter on eprobe event correctly

 - Add filter on eprobe to the README file in tracefs

 - Fix optprobes to check whether there is 'under unoptimizing' optprobe
   when optimizing another kprobe correctly

 - Fix optprobe to check whether there is 'under unoptimizing' optprobe
   when fetching the original instruction correctly

 - Fix optprobe to free 'forcibly unoptimized' optprobe correctly

* tag 'probes-v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing/eprobe: no need to check for negative ret value for snprintf
  test_kprobes: Add recursed kprobe test case
  tracing/probe: add a char type to show the character value of traced arguments
  selftests/ftrace: Fix probepoint testcase to ignore __pfx_* symbols
  selftests/ftrace: Fix eprobe syntax test case to check filter support
  tracing/eprobe: Fix to add filter on eprobe description in README file
  x86/kprobes: Fix arch_check_optimized_kprobe check within optimized_kprobe range
  x86/kprobes: Fix __recover_optprobed_insn check optimizing logic
  kprobes: Fix to handle forcibly unoptimized kprobes on freeing_list
2023-02-23 13:03:08 -08:00
Linus Torvalds
b72b5fecc1 tracing updates for 6.3:
- Add function names as a way to filter function addresses
 
 - Add sample module to test ftrace ops and dynamic trampolines
 
 - Allow stack traces to be passed from beginning event to end event for
   synthetic events. This will allow seeing the stack trace of when a task is
   scheduled out and recorded when it gets scheduled back in.
 
 - Add trace event helper __get_buf() to use as a temporary buffer when printing
   out trace event output.
 
 - Add kernel command line to create trace instances on boot up.
 
 - Add enabling of events to instances created at boot up.
 
 - Add trace_array_puts() to write into instances.
 
 - Allow boot instances to take a snapshot at the end of boot up.
 
 - Allow live patch modules to include trace events
 
 - Minor fixes and clean ups
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Merge tag 'trace-v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt:

 - Add function names as a way to filter function addresses

 - Add sample module to test ftrace ops and dynamic trampolines

 - Allow stack traces to be passed from beginning event to end event for
   synthetic events. This will allow seeing the stack trace of when a
   task is scheduled out and recorded when it gets scheduled back in.

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   printing out trace event output.

 - Add kernel command line to create trace instances on boot up.

 - Add enabling of events to instances created at boot up.

 - Add trace_array_puts() to write into instances.

 - Allow boot instances to take a snapshot at the end of boot up.

 - Allow live patch modules to include trace events

 - Minor fixes and clean ups

* tag 'trace-v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (31 commits)
  tracing: Remove unnecessary NULL assignment
  tracepoint: Allow livepatch module add trace event
  tracing: Always use canonical ftrace path
  tracing/histogram: Fix stacktrace histogram Documententation
  tracing/histogram: Fix stacktrace key
  tracing/histogram: Fix a few problems with stacktrace variable printing
  tracing: Add BUILD_BUG() to make sure stacktrace fits in strings
  tracing/histogram: Don't use strlen to find length of stacktrace variables
  tracing: Allow boot instances to have snapshot buffers
  tracing: Add trace_array_puts() to write into instance
  tracing: Add enabling of events to boot instances
  tracing: Add creation of instances at boot command line
  tracing: Fix trace_event_raw_event_synth() if else statement
  samples: ftrace: Make some global variables static
  ftrace: sample: avoid open-coded 64-bit division
  samples: ftrace: Include the nospec-branch.h only for x86
  tracing: Acquire buffer from temparary trace sequence
  tracing/histogram: Wrap remaining shell snippets in code blocks
  tracing/osnoise: No need for schedule_hrtimeout range
  bpf/tracing: Use stage6 of tracing to not duplicate macros
  ...
2023-02-23 10:20:49 -08:00
Linus Torvalds
1f2d9ffc7a Scheduler updates in this cycle are:
- Improve the scalability of the CFS bandwidth unthrottling logic
    with large number of CPUs.
 
  - Fix & rework various cpuidle routines, simplify interaction with
    the generic scheduler code. Add __cpuidle methods as noinstr to
    objtool's noinstr detection and fix boatloads of cpuidle bugs & quirks.
 
  - Add new ABI: introduce MEMBARRIER_CMD_GET_REGISTRATIONS,
    to query previously issued registrations.
 
  - Limit scheduler slice duration to the sysctl_sched_latency period,
    to improve scheduling granularity with a large number of SCHED_IDLE
    tasks.
 
  - Debuggability enhancement on sys_exit(): warn about disabled IRQs,
    but also enable them to prevent a cascade of followup problems and
    repeat warnings.
 
  - Fix the rescheduling logic in prio_changed_dl().
 
  - Micro-optimize cpufreq and sched-util methods.
 
  - Micro-optimize ttwu_runnable()
 
  - Micro-optimize the idle-scanning in update_numa_stats(),
    select_idle_capacity() and steal_cookie_task().
 
  - Update the RSEQ code & self-tests
 
  - Constify various scheduler methods
 
  - Remove unused methods
 
  - Refine __init tags
 
  - Documentation updates
 
  - ... Misc other cleanups, fixes
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2023-02-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Ingo Molnar:

 - Improve the scalability of the CFS bandwidth unthrottling logic with
   large number of CPUs.

 - Fix & rework various cpuidle routines, simplify interaction with the
   generic scheduler code. Add __cpuidle methods as noinstr to objtool's
   noinstr detection and fix boatloads of cpuidle bugs & quirks.

 - Add new ABI: introduce MEMBARRIER_CMD_GET_REGISTRATIONS, to query
   previously issued registrations.

 - Limit scheduler slice duration to the sysctl_sched_latency period, to
   improve scheduling granularity with a large number of SCHED_IDLE
   tasks.

 - Debuggability enhancement on sys_exit(): warn about disabled IRQs,
   but also enable them to prevent a cascade of followup problems and
   repeat warnings.

 - Fix the rescheduling logic in prio_changed_dl().

 - Micro-optimize cpufreq and sched-util methods.

 - Micro-optimize ttwu_runnable()

 - Micro-optimize the idle-scanning in update_numa_stats(),
   select_idle_capacity() and steal_cookie_task().

 - Update the RSEQ code & self-tests

 - Constify various scheduler methods

 - Remove unused methods

 - Refine __init tags

 - Documentation updates

 - Misc other cleanups, fixes

* tag 'sched-core-2023-02-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (110 commits)
  sched/rt: pick_next_rt_entity(): check list_entry
  sched/deadline: Add more reschedule cases to prio_changed_dl()
  sched/fair: sanitize vruntime of entity being placed
  sched/fair: Remove capacity inversion detection
  sched/fair: unlink misfit task from cpu overutilized
  objtool: mem*() are not uaccess safe
  cpuidle: Fix poll_idle() noinstr annotation
  sched/clock: Make local_clock() noinstr
  sched/clock/x86: Mark sched_clock() noinstr
  x86/pvclock: Improve atomic update of last_value in pvclock_clocksource_read()
  x86/atomics: Always inline arch_atomic64*()
  cpuidle: tracing, preempt: Squash _rcuidle tracing
  cpuidle: tracing: Warn about !rcu_is_watching()
  cpuidle: lib/bug: Disable rcu_is_watching() during WARN/BUG
  cpuidle: drivers: firmware: psci: Dont instrument suspend code
  KVM: selftests: Fix build of rseq test
  exit: Detect and fix irq disabled state in oops
  cpuidle, arm64: Fix the ARM64 cpuidle logic
  cpuidle: mvebu: Fix duplicate flags assignment
  sched/fair: Limit sched slice duration
  ...
2023-02-20 17:41:08 -08:00
Donglin Peng
8478cca1e3 tracing/probe: add a char type to show the character value of traced arguments
There are scenes that we want to show the character value of traced
arguments other than a decimal or hexadecimal or string value for debug
convinience. I add a new type named 'char' to do it and a new test case
file named 'kprobe_args_char.tc' to do selftest for char type.

For example:

The to be traced function is 'void demo_func(char type, char *name);', we
can add a kprobe event as follows to show argument values as we want:

echo  'p:myprobe demo_func $arg1:char +0($arg2):char[5]' > kprobe_events

we will get the following trace log:

... myprobe: (demo_func+0x0/0x29) arg1='A' arg2={'b','p','f','1',''}

Link: https://lore.kernel.org/all/20221219110613.367098-1-dolinux.peng@gmail.com/

Signed-off-by: Donglin Peng <dolinux.peng@gmail.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2023-02-21 08:52:42 +09:00
Masami Hiramatsu (Google)
133921530c tracing/eprobe: Fix to add filter on eprobe description in README file
Fix to add a description of the filter on eprobe in README file. This
is required to identify the kernel supports the filter on eprobe or not.

Link: https://lore.kernel.org/all/167309833728.640500.12232259238201433587.stgit@devnote3/

Fixes: 752be5c5c9 ("tracing/eprobe: Add eprobe filter support")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-02-21 08:49:16 +09:00
Ross Zwisler
2455f0e124 tracing: Always use canonical ftrace path
The canonical location for the tracefs filesystem is at /sys/kernel/tracing.

But, from Documentation/trace/ftrace.rst:

  Before 4.1, all ftrace tracing control files were within the debugfs
  file system, which is typically located at /sys/kernel/debug/tracing.
  For backward compatibility, when mounting the debugfs file system,
  the tracefs file system will be automatically mounted at:

  /sys/kernel/debug/tracing

Many comments and Kconfig help messages in the tracing code still refer
to this older debugfs path, so let's update them to avoid confusion.

Link: https://lore.kernel.org/linux-trace-kernel/20230215223350.2658616-2-zwisler@google.com

Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com>
Signed-off-by: Ross Zwisler <zwisler@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-02-18 14:34:09 -05:00
Steven Rostedt (Google)
9c1c251d67 tracing: Allow boot instances to have snapshot buffers
Add to ftrace_boot_snapshot, "=<instance>" name, where the instance will
get a snapshot buffer, and will take a snapshot at the end of boot (which
will save the boot traces).

Link: https://lkml.kernel.org/r/20230207173026.792774721@goodmis.org

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ross Zwisler <zwisler@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-02-07 12:49:56 -05:00
Steven Rostedt (Google)
d503b8f747 tracing: Add trace_array_puts() to write into instance
Add a generic trace_array_puts() that can be used to "trace_puts()" into
an allocated trace_array instance. This is just another variant of
trace_array_printk().

Link: https://lkml.kernel.org/r/20230207173026.584717290@goodmis.org

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ross Zwisler <zwisler@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-02-07 12:49:56 -05:00
Steven Rostedt (Google)
c484648083 tracing: Add enabling of events to boot instances
Add the format of:

  trace_instance=foo,sched:sched_switch,irq_handler_entry,initcall

That will create the "foo" instance and enable the sched_switch event
(here were the "sched" system is explicitly specified), the
irq_handler_entry event, and all events under the system initcall.

Link: https://lkml.kernel.org/r/20230207173026.386114535@goodmis.org

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ross Zwisler <zwisler@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-02-07 12:49:56 -05:00
Steven Rostedt (Google)
cb1f98c5e5 tracing: Add creation of instances at boot command line
Add kernel command line to add tracing instances. This only creates
instances at boot but still does not enable any events to them. Later
changes will extend this command line to add enabling of events, filters,
and triggers. As well as possibly redirecting trace_printk()!

Link: https://lkml.kernel.org/r/20230207173026.186210158@goodmis.org

Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ross Zwisler <zwisler@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-02-07 12:49:56 -05:00
Shiju Jose
3e46d910d8 tracing: Fix poll() and select() do not work on per_cpu trace_pipe and trace_pipe_raw
poll() and select() on per_cpu trace_pipe and trace_pipe_raw do not work
since kernel 6.1-rc6. This issue is seen after the commit
42fb0a1e84 ("tracing/ring-buffer: Have
polling block on watermark").

This issue is firstly detected and reported, when testing the CXL error
events in the rasdaemon and also erified using the test application for poll()
and select().

This issue occurs for the per_cpu case, when calling the ring_buffer_poll_wait(),
in kernel/trace/ring_buffer.c, with the buffer_percent > 0 and then wait until the
percentage of pages are available. The default value set for the buffer_percent is 50
in the kernel/trace/trace.c.

As a fix, allow userspace application could set buffer_percent as 0 through
the buffer_percent_fops, so that the task will wake up as soon as data is added
to any of the specific cpu buffer.

Link: https://lore.kernel.org/linux-trace-kernel/20230202182309.742-2-shiju.jose@huawei.com

Cc: <mhiramat@kernel.org>
Cc: <mchehab@kernel.org>
Cc: <linux-edac@vger.kernel.org>
Cc: stable@vger.kernel.org
Fixes: 42fb0a1e84 ("tracing/ring-buffer: Have polling block on watermark")
Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-02-02 16:15:53 -05:00
Ingo Molnar
57a30218fa Linux 6.2-rc6
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Merge tag 'v6.2-rc6' into sched/core, to pick up fixes

Pick up fixes before merging another batch of cpuidle updates.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2023-01-31 15:01:20 +01:00
Steven Rostedt (Google)
b81a3a100c tracing/histogram: Add simple tests for stacktrace usage of synthetic events
Update the selftests to include a test of passing a stacktrace between the
events of a synthetic event.

Link: https://lkml.kernel.org/r/20230117152236.475439286@goodmis.org

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Ross Zwisler <zwisler@google.com>
Cc: Ching-lin Yu <chinglinyu@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-01-25 10:31:24 -05:00
Steven Rostedt (Google)
3bb06eb6e9 tracing: Make sure trace_printk() can output as soon as it can be used
Currently trace_printk() can be used as soon as early_trace_init() is
called from start_kernel(). But if a crash happens, and
"ftrace_dump_on_oops" is set on the kernel command line, all you get will
be:

  [    0.456075]   <idle>-0         0dN.2. 347519us : Unknown type 6
  [    0.456075]   <idle>-0         0dN.2. 353141us : Unknown type 6
  [    0.456075]   <idle>-0         0dN.2. 358684us : Unknown type 6

This is because the trace_printk() event (type 6) hasn't been registered
yet. That gets done via an early_initcall(), which may be early, but not
early enough.

Instead of registering the trace_printk() event (and other ftrace events,
which are not trace events) via an early_initcall(), have them registered at
the same time that trace_printk() can be used. This way, if there is a
crash before early_initcall(), then the trace_printk()s will actually be
useful.

Link: https://lkml.kernel.org/r/20230104161412.019f6c55@gandalf.local.home

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Fixes: e725c731e3 ("tracing: Split tracing initialization into two for early initialization")
Reported-by: "Joel Fernandes (Google)" <joel@joelfernandes.org>
Tested-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-01-24 11:27:29 -05:00
Peter Zijlstra
408b961146 tracing: WARN on rcuidle
ARCH_WANTS_NO_INSTR (a superset of CONFIG_GENERIC_ENTRY) disallows any
and all tracing when RCU isn't enabled.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20230112195541.416110581@infradead.org
2023-01-13 11:48:16 +01:00
Linus Torvalds
af9b3fa15d Trace probes updates for 6.2:
- New "symstr" type for dynamic events that writes the name of the
   function+offset into the ring buffer and not just the address
 
 - Prevent kernel symbol processing on addresses in user space probes
   (uprobes).
 
 - And minor fixes and clean ups
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Merge tag 'trace-probes-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull trace probes updates from Steven Rostedt:

 - New "symstr" type for dynamic events that writes the name of the
   function+offset into the ring buffer and not just the address

 - Prevent kernel symbol processing on addresses in user space probes
   (uprobes).

 - And minor fixes and clean ups

* tag 'trace-probes-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing/probes: Reject symbol/symstr type for uprobe
  tracing/probes: Add symstr type for dynamic events
  kprobes: kretprobe events missing on 2-core KVM guest
  kprobes: Fix check for probe enabled in kill_kprobe()
  test_kprobes: Fix implicit declaration error of test_kprobes
  tracing: Fix race where eprobes can be called before the event
2022-12-21 18:57:24 -08:00
Masami Hiramatsu (Google)
b26a124cbf tracing/probes: Add symstr type for dynamic events
Add 'symstr' type for storing the kernel symbol as a string data
instead of the symbol address. This allows us to filter the
events by wildcard symbol name.

e.g.
  # echo 'e:wqfunc workqueue.workqueue_execute_start symname=$function:symstr' >> dynamic_events
  # cat events/eprobes/wqfunc/format
  name: wqfunc
  ID: 2110
  format:
  	field:unsigned short common_type;	offset:0;	size:2;	signed:0;
  	field:unsigned char common_flags;	offset:2;	size:1;	signed:0;
  	field:unsigned char common_preempt_count;	offset:3;	size:1;	signed:0;
  	field:int common_pid;	offset:4;	size:4;	signed:1;

  	field:__data_loc char[] symname;	offset:8;	size:4;	signed:1;

  print fmt: " symname=\"%s\"", __get_str(symname)

Note that there is already 'symbol' type which just change the
print format (so it still stores the symbol address in the tracing
ring buffer.) On the other hand, 'symstr' type stores the actual
"symbol+offset/size" data as a string.

Link: https://lore.kernel.org/all/166679930847.1528100.4124308529180235965.stgit@devnote3/

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2022-12-15 08:48:57 +09:00
Guilherme G. Piccoli
ea47666ca4 tracing: Improve panic/die notifiers
Currently the tracing dump_on_oops feature is implemented through
separate notifiers, one for die/oops and the other for panic;
given they have the same functionality, let's unify them.

Also improve the function comment and change the priority of the
notifier to make it execute earlier, avoiding showing useless trace
data (like the callback names for the other notifiers); finally,
we also removed an unnecessary header inclusion.

Link: https://lkml.kernel.org/r/20220819221731.480795-7-gpiccoli@igalia.com

Cc: Petr Mladek <pmladek@suse.com>
Cc: Sergei Shtylyov <sergei.shtylyov@gmail.com>
Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-12-14 11:17:55 -05:00
Yang Jihong
c1ac03af6e tracing: Fix infinite loop in tracing_read_pipe on overflowed print_trace_line
print_trace_line may overflow seq_file buffer. If the event is not
consumed, the while loop keeps peeking this event, causing a infinite loop.

Link: https://lkml.kernel.org/r/20221129113009.182425-1-yangjihong1@huawei.com

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
Fixes: 088b1e427d ("ftrace: pipe fixes")
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-12-12 10:21:46 -05:00
Masami Hiramatsu (Google)
e25e43a4e5 tracing: Fix complicated dependency of CONFIG_TRACER_MAX_TRACE
Both CONFIG_OSNOISE_TRACER and CONFIG_HWLAT_TRACER partially enables the
CONFIG_TRACER_MAX_TRACE code, but that is complicated and has
introduced a bug; It declares tracing_max_lat_fops data structure outside
of #ifdefs, but since it is defined only when CONFIG_TRACER_MAX_TRACE=y
or CONFIG_HWLAT_TRACER=y, if only CONFIG_OSNOISE_TRACER=y, that
declaration comes to a definition(!).

To fix this issue, and do not repeat the similar problem, makes
CONFIG_OSNOISE_TRACER and CONFIG_HWLAT_TRACER enables the
CONFIG_TRACER_MAX_TRACE always. It has there benefits;
- Fix the tracing_max_lat_fops bug
- Simplify the #ifdefs
- CONFIG_TRACER_MAX_TRACE code is fully enabled, or not.

Link: https://lore.kernel.org/linux-trace-kernel/167033628155.4111793.12185405690820208159.stgit@devnote3

Fixes: 424b650f35 ("tracing: Fix missing osnoise tracer on max_latency")
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: stable@vger.kernel.org
Reported-by: David Howells <dhowells@redhat.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://lore.kernel.org/all/166992525941.1716618.13740663757583361463.stgit@warthog.procyon.org.uk/ (original thread and v1)
Link: https://lore.kernel.org/all/202212052253.VuhZ2ulJ-lkp@intel.com/T/#u (v1 error report)
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-12-09 23:48:05 -05:00
Masami Hiramatsu (Google)
ccf47f5cc4 tracing: Add nohitcount option for suppressing display of raw hitcount
Add 'nohitcount' ('NOHC' for short) option for suppressing display of
the raw hitcount column in the histogram.
Note that you must specify at least one value except raw 'hitcount'
when you specify this nohitcount option.

  # cd /sys/kernel/debug/tracing/
  # echo hist:keys=pid:vals=runtime.percent,runtime.graph:sort=pid:NOHC > \
        events/sched/sched_stat_runtime/trigger
  # sleep 10
  # cat events/sched/sched_stat_runtime/hist
 # event histogram
 #
 # trigger info: hist:keys=pid:vals=runtime.percent,runtime.graph:sort=pid:size=2048:nohitcount  [active]
 #

 { pid:          8 }  runtime (%):   3.02  runtime: #
 { pid:         14 }  runtime (%):   2.25  runtime:
 { pid:         16 }  runtime (%):   2.25  runtime:
 { pid:         26 }  runtime (%):   0.17  runtime:
 { pid:         61 }  runtime (%):  11.52  runtime: ####
 { pid:         67 }  runtime (%):   1.56  runtime:
 { pid:         68 }  runtime (%):   0.84  runtime:
 { pid:         76 }  runtime (%):   0.92  runtime:
 { pid:        117 }  runtime (%):   2.50  runtime: #
 { pid:        146 }  runtime (%):  49.88  runtime: ####################
 { pid:        157 }  runtime (%):  16.63  runtime: ######
 { pid:        158 }  runtime (%):   8.38  runtime: ###

Link: https://lore.kernel.org/linux-trace-kernel/166610814787.56030.4980636083486339906.stgit@devnote2

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Tested-by: Tom Zanussi <zanussi@kernel.org>
2022-12-09 23:48:05 -05:00
Masami Hiramatsu (Google)
a2c54256de tracing: Add .graph suffix option to histogram value
Add the .graph suffix which shows the bar graph of the histogram value.

For example, the below example shows that the bar graph
of the histogram of the runtime for each tasks.

------
  # cd /sys/kernel/debug/tracing/
  # echo hist:keys=pid:vals=runtime.graph:sort=pid > \
   events/sched/sched_stat_runtime/trigger
  # sleep 10
  # cat events/sched/sched_stat_runtime/hist
 # event histogram
 #
 # trigger info: hist:keys=pid:vals=hitcount,runtime.graph:sort=pid:size=2048 [active]
 #

 { pid:         14 } hitcount:          2  runtime:
 { pid:         16 } hitcount:          8  runtime:
 { pid:         26 } hitcount:          1  runtime:
 { pid:         57 } hitcount:          3  runtime:
 { pid:         61 } hitcount:         20  runtime: ###
 { pid:         66 } hitcount:          2  runtime:
 { pid:         70 } hitcount:          3  runtime:
 { pid:         72 } hitcount:          2  runtime:
 { pid:        145 } hitcount:         14  runtime: ####################
 { pid:        152 } hitcount:          5  runtime: #######
 { pid:        153 } hitcount:          2  runtime: ####

 Totals:
     Hits: 62
     Entries: 11
     Dropped: 0
-------

Link: https://lore.kernel.org/linux-trace-kernel/166610813953.56030.10944148382315789485.stgit@devnote2

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Tested-by: Tom Zanussi <zanussi@kernel.org>
2022-12-09 23:48:04 -05:00
Masami Hiramatsu (Google)
abaa5258ce tracing: Add .percent suffix option to histogram values
Add .percent suffix option to show the histogram values in percentage.
This feature is useful when we need yo undersntand the overall trend
for the histograms of large values.
E.g. this shows the runtime percentage for each tasks.

------
  # cd /sys/kernel/debug/tracing/
  # echo hist:keys=pid:vals=hitcount,runtime.percent:sort=pid > \
    events/sched/sched_stat_runtime/trigger
  # sleep 10
  # cat events/sched/sched_stat_runtime/hist
 # event histogram
 #
 # trigger info: hist:keys=pid:vals=hitcount,runtime.percent:sort=pid:size=2048 [active]
 #

 { pid:          8 } hitcount:          7  runtime (%):   4.14
 { pid:         14 } hitcount:          5  runtime (%):   3.69
 { pid:         16 } hitcount:         11  runtime (%):   3.41
 { pid:         61 } hitcount:         41  runtime (%):  19.75
 { pid:         65 } hitcount:          4  runtime (%):   1.48
 { pid:         70 } hitcount:          6  runtime (%):   3.60
 { pid:         72 } hitcount:          2  runtime (%):   1.10
 { pid:        144 } hitcount:         10  runtime (%):  32.01
 { pid:        151 } hitcount:          8  runtime (%):  22.66
 { pid:        152 } hitcount:          2  runtime (%):   8.10

 Totals:
     Hits: 96
     Entries: 10
     Dropped: 0
-----

Link: https://lore.kernel.org/linux-trace-kernel/166610813077.56030.4238090506973562347.stgit@devnote2

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Tested-by: Tom Zanussi <zanussi@kernel.org>
2022-12-09 23:48:04 -05:00
Xiu Jianfeng
a76d4648a0 tracing: Make tracepoint_print_iter static
After change in commit 4239174570 ("tracing: Make tracepoint_printk a
static_key"), this symbol is not used outside of the file, so mark it
static.

Link: https://lkml.kernel.org/r/20221122091456.72055-1-xiujianfeng@huawei.com

Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-11-23 19:08:31 -05:00
Song Chen
04aabc32fb ring_buffer: Remove unused "event" parameter
After commit a389d86f7f ("ring-buffer: Have nested events still record
running time stamp"), the "event" parameter is no longer used in either
ring_buffer_unlock_commit() or rb_commit(). Best to remove it.

Link: https://lkml.kernel.org/r/1666274811-24138-1-git-send-email-chensong_2000@189.cn

Signed-off-by: Song Chen <chensong_2000@189.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-11-23 19:08:30 -05:00
Steven Rostedt (Google)
e18eb8783e tracing: Add tracing_reset_all_online_cpus_unlocked() function
Currently the tracing_reset_all_online_cpus() requires the
trace_types_lock held. But only one caller of this function actually has
that lock held before calling it, and the other just takes the lock so
that it can call it. More users of this function is needed where the lock
is not held.

Add a tracing_reset_all_online_cpus_unlocked() function for the one use
case that calls it without being held, and also add a lockdep_assert to
make sure it is held when called.

Then have tracing_reset_all_online_cpus() take the lock internally, such
that callers do not need to worry about taking it.

Link: https://lkml.kernel.org/r/20221123192741.658273220@goodmis.org

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-11-23 19:06:11 -05:00
Zheng Yejian
067df9e0ad tracing: Fix potential null-pointer-access of entry in list 'tr->err_log'
Entries in list 'tr->err_log' will be reused after entry number
exceed TRACING_LOG_ERRS_MAX.

The cmd string of the to be reused entry will be freed first then
allocated a new one. If the allocation failed, then the entry will
still be in list 'tr->err_log' but its 'cmd' field is set to be NULL,
later access of 'cmd' is risky.

Currently above problem can cause the loss of 'cmd' information of first
entry in 'tr->err_log'. When execute `cat /sys/kernel/tracing/error_log`,
reproduce logs like:
  [   37.495100] trace_kprobe: error: Maxactive is not for kprobe(null) ^
  [   38.412517] trace_kprobe: error: Maxactive is not for kprobe
    Command: p4:myprobe2 do_sys_openat2
            ^

Link: https://lore.kernel.org/linux-trace-kernel/20221114104632.3547266-1-zhengyejian1@huawei.com

Fixes: 1581a884b7 ("tracing: Remove size restriction on tracing_log_err cmd strings")
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-11-17 20:41:01 -05:00
Wang Yufen
649e72070c tracing: Fix memory leak in tracing_read_pipe()
kmemleak reports this issue:

unreferenced object 0xffff888105a18900 (size 128):
  comm "test_progs", pid 18933, jiffies 4336275356 (age 22801.766s)
  hex dump (first 32 bytes):
    25 73 00 90 81 88 ff ff 26 05 00 00 42 01 58 04  %s......&...B.X.
    03 00 00 00 02 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000560143a1>] __kmalloc_node_track_caller+0x4a/0x140
    [<000000006af00822>] krealloc+0x8d/0xf0
    [<00000000c309be6a>] trace_iter_expand_format+0x99/0x150
    [<000000005a53bdb6>] trace_check_vprintf+0x1e0/0x11d0
    [<0000000065629d9d>] trace_event_printf+0xb6/0xf0
    [<000000009a690dc7>] trace_raw_output_bpf_trace_printk+0x89/0xc0
    [<00000000d22db172>] print_trace_line+0x73c/0x1480
    [<00000000cdba76ba>] tracing_read_pipe+0x45c/0x9f0
    [<0000000015b58459>] vfs_read+0x17b/0x7c0
    [<000000004aeee8ed>] ksys_read+0xed/0x1c0
    [<0000000063d3d898>] do_syscall_64+0x3b/0x90
    [<00000000a06dda7f>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

iter->fmt alloced in
  tracing_read_pipe() -> .. ->trace_iter_expand_format(), but not
freed, to fix, add free in tracing_release_pipe()

Link: https://lkml.kernel.org/r/1667819090-4643-1-git-send-email-wangyufen@huawei.com

Cc: stable@vger.kernel.org
Fixes: efbbdaa22b ("tracing: Show real address for trace event arguments")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Wang Yufen <wangyufen@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-11-16 20:29:00 -05:00
Steven Rostedt (Google)
42fb0a1e84 tracing/ring-buffer: Have polling block on watermark
Currently the way polling works on the ring buffer is broken. It will
return immediately if there's any data in the ring buffer whereas a read
will block until the watermark (defined by the tracefs buffer_percent file)
is hit.

That is, a select() or poll() will return as if there's data available,
but then the following read will block. This is broken for the way
select()s and poll()s are supposed to work.

Have the polling on the ring buffer also block the same way reads and
splice does on the ring buffer.

Link: https://lkml.kernel.org/r/20221020231427.41be3f26@gandalf.local.home

Cc: Linux Trace Kernel <linux-trace-kernel@vger.kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Primiano Tucci <primiano@google.com>
Cc: stable@vger.kernel.org
Fixes: 1e0d6714ac ("ring-buffer: Do not wake up a splice waiter when page is not full")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-11-16 17:13:04 -05:00
Steven Rostedt (Google)
a541a9559b tracing: Do not free snapshot if tracer is on cmdline
The ftrace_boot_snapshot and alloc_snapshot cmdline options allocate the
snapshot buffer at boot up for use later. The ftrace_boot_snapshot in
particular requires the snapshot to be allocated because it will take a
snapshot at the end of boot up allowing to see the traces that happened
during boot so that it's not lost when user space takes over.

When a tracer is registered (started) there's a path that checks if it
requires the snapshot buffer or not, and if it does not and it was
allocated it will do a synchronization and free the snapshot buffer.

This is only required if the previous tracer was using it for "max
latency" snapshots, as it needs to make sure all max snapshots are
complete before freeing. But this is only needed if the previous tracer
was using the snapshot buffer for latency (like irqoff tracer and
friends). But it does not make sense to free it, if the previous tracer
was not using it, and the snapshot was allocated by the cmdline
parameters. This basically takes away the point of allocating it in the
first place!

Note, the allocated snapshot worked fine for just trace events, but fails
when a tracer is enabled on the cmdline.

Further investigation, this goes back even further and it does not require
a tracer on the cmdline to fail. Simply enable snapshots and then enable a
tracer, and it will remove the snapshot.

Link: https://lkml.kernel.org/r/20221005113757.041df7fe@gandalf.local.home

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org
Fixes: 45ad21ca55 ("tracing: Have trace_array keep track if snapshot buffer is allocated")
Reported-by: Ross Zwisler <zwisler@kernel.org>
Tested-by: Ross Zwisler <zwisler@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-10-05 22:18:23 -04:00
Colin Ian King
e841e8bfac tracing: Fix spelling mistake "preapre" -> "prepare"
There is a spelling mistake in the trace text. Fix it.

Link: https://lkml.kernel.org/r/20220928215828.66325-1-colin.i.king@gmail.com

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-09-29 10:17:35 -04:00
Steven Rostedt (Google)
2b0fd9a59b tracing: Wake up waiters when tracing is disabled
When tracing is disabled, there's no reason that waiters should stay
waiting, wake them up, otherwise tasks get stuck when they should be
flushing the buffers.

Cc: stable@vger.kernel.org
Fixes: e30f53aad2 ("tracing: Do not busy wait in buffer splice")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-09-29 10:17:35 -04:00
Steven Rostedt (Google)
01b2a52171 tracing: Add ioctl() to force ring buffer waiters to wake up
If a process is waiting on the ring buffer for data, there currently isn't
a clean way to force it to wake up. Add an ioctl call that will force any
tasks that are waiting on the trace_pipe_raw file to wake up.

Link: https://lkml.kernel.org/r/20220929095029.117f913f@gandalf.local.home

Cc: stable@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: e30f53aad2 ("tracing: Do not busy wait in buffer splice")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-09-29 10:17:18 -04:00
Steven Rostedt (Google)
f3ddb74ad0 tracing: Wake up ring buffer waiters on closing of the file
When the file that represents the ring buffer is closed, there may be
waiters waiting on more input from the ring buffer. Call
ring_buffer_wake_waiters() to wake up any waiters when the file is
closed.

Link: https://lkml.kernel.org/r/20220927231825.182416969@goodmis.org

Cc: stable@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: e30f53aad2 ("tracing: Do not busy wait in buffer splice")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-09-28 20:28:13 -04:00
Waiman Long
c0a581d712 tracing: Disable interrupt or preemption before acquiring arch_spinlock_t
It was found that some tracing functions in kernel/trace/trace.c acquire
an arch_spinlock_t with preemption and irqs enabled. An example is the
tracing_saved_cmdlines_size_read() function which intermittently causes
a "BUG: using smp_processor_id() in preemptible" warning when the LTP
read_all_proc test is run.

That can be problematic in case preemption happens after acquiring the
lock. Add the necessary preemption or interrupt disabling code in the
appropriate places before acquiring an arch_spinlock_t.

The convention here is to disable preemption for trace_cmdline_lock and
interupt for max_lock.

Link: https://lkml.kernel.org/r/20220922145622.1744826-1-longman@redhat.com

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: stable@vger.kernel.org
Fixes: a35873a099 ("tracing: Add conditional snapshot")
Fixes: 939c7a4f04 ("tracing: Introduce saved_cmdlines_size file")
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-09-27 14:48:11 -04:00
Linus Torvalds
965a9d75e3 Tracing updates for 5.20 / 6.0
- Runtime verification infrastructure
   This is the biggest change for this pull request. It introduces the
   runtime verification that is necessary for running Linux on safety
   critical systems. It allows for deterministic automata models to be
   inserted into the kernel that will attach to tracepoints, where the
   information on these tracepoints will move the model from state to state.
   If a state is encountered that does not belong to the model, it will then
   activate a given reactor, that could just inform the user or even panic
   the kernel (for which safety critical systems will detect and can recover
   from).
 
 - Two monitor models are also added: Wakeup In Preemptive (WIP - not to be
   confused with "work in progress"), and Wakeup While Not Running (WWNR).
 
 - Added __vstring() helper to the TRACE_EVENT() macro to replace several
   vsnprintf() usages that were all doing it wrong.
 
 - eprobes now can have their event autogenerated when the event name is left
   off.
 
 - The rest is various cleanups and fixes.
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Merge tag 'trace-v6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:

 - Runtime verification infrastructure

   This is the biggest change here. It introduces the runtime
   verification that is necessary for running Linux on safety critical
   systems.

   It allows for deterministic automata models to be inserted into the
   kernel that will attach to tracepoints, where the information on
   these tracepoints will move the model from state to state.

   If a state is encountered that does not belong to the model, it will
   then activate a given reactor, that could just inform the user or
   even panic the kernel (for which safety critical systems will detect
   and can recover from).

 - Two monitor models are also added: Wakeup In Preemptive (WIP - not to
   be confused with "work in progress"), and Wakeup While Not Running
   (WWNR).

 - Added __vstring() helper to the TRACE_EVENT() macro to replace
   several vsnprintf() usages that were all doing it wrong.

 - eprobes now can have their event autogenerated when the event name is
   left off.

 - The rest is various cleanups and fixes.

* tag 'trace-v6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (50 commits)
  rv: Unlock on error path in rv_unregister_reactor()
  tracing: Use alignof__(struct {type b;}) instead of offsetof()
  tracing/eprobe: Show syntax error logs in error_log file
  scripts/tracing: Fix typo 'the the' in comment
  tracepoints: It is CONFIG_TRACEPOINTS not CONFIG_TRACEPOINT
  tracing: Use free_trace_buffer() in allocate_trace_buffers()
  tracing: Use a struct alignof to determine trace event field alignment
  rv/reactor: Add the panic reactor
  rv/reactor: Add the printk reactor
  rv/monitor: Add the wwnr monitor
  rv/monitor: Add the wip monitor
  rv/monitor: Add the wip monitor skeleton created by dot2k
  Documentation/rv: Add deterministic automata instrumentation documentation
  Documentation/rv: Add deterministic automata monitor synthesis documentation
  tools/rv: Add dot2k
  Documentation/rv: Add deterministic automaton documentation
  tools/rv: Add dot2c
  Documentation/rv: Add a basic documentation
  rv/include: Add instrumentation helper functions
  rv/include: Add deterministic automata monitor definition via C macros
  ...
2022-08-05 09:41:12 -07:00
Linus Torvalds
7d9d077c78 RCU pull request for v5.20 (or whatever)
This pull request contains the following branches:
 
 doc.2022.06.21a: Documentation updates.
 
 fixes.2022.07.19a: Miscellaneous fixes.
 
 nocb.2022.07.19a: Callback-offload updates, perhaps most notably a new
 	RCU_NOCB_CPU_DEFAULT_ALL Kconfig option that causes all CPUs to
 	be offloaded at boot time, regardless of kernel boot parameters.
 	This is useful to battery-powered systems such as ChromeOS
 	and Android.  In addition, a new RCU_NOCB_CPU_CB_BOOST kernel
 	boot parameter prevents offloaded callbacks from interfering
 	with real-time workloads and with energy-efficiency mechanisms.
 
 poll.2022.07.21a: Polled grace-period updates, perhaps most notably
 	making these APIs account for both normal and expedited grace
 	periods.
 
 rcu-tasks.2022.06.21a: Tasks RCU updates, perhaps most notably reducing
 	the CPU overhead of RCU tasks trace grace periods by more than
 	a factor of two on a system with 15,000 tasks.	The reduction
 	is expected to increase with the number of tasks, so it seems
 	reasonable to hypothesize that a system with 150,000 tasks might
 	see a 20-fold reduction in CPU overhead.
 
 torture.2022.06.21a: Torture-test updates.
 
 ctxt.2022.07.05a: Updates that merge RCU's dyntick-idle tracking into
 	context tracking, thus reducing the overhead of transitioning to
 	kernel mode from either idle or nohz_full userspace execution
 	for kernels that track context independently of RCU.  This is
 	expected to be helpful primarily for kernels built with
 	CONFIG_NO_HZ_FULL=y.
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Merge tag 'rcu.2022.07.26a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

Pull RCU updates from Paul McKenney:

 - Documentation updates

 - Miscellaneous fixes

 - Callback-offload updates, perhaps most notably a new
   RCU_NOCB_CPU_DEFAULT_ALL Kconfig option that causes all CPUs to be
   offloaded at boot time, regardless of kernel boot parameters.

   This is useful to battery-powered systems such as ChromeOS and
   Android. In addition, a new RCU_NOCB_CPU_CB_BOOST kernel boot
   parameter prevents offloaded callbacks from interfering with
   real-time workloads and with energy-efficiency mechanisms

 - Polled grace-period updates, perhaps most notably making these APIs
   account for both normal and expedited grace periods

 - Tasks RCU updates, perhaps most notably reducing the CPU overhead of
   RCU tasks trace grace periods by more than a factor of two on a
   system with 15,000 tasks.

   The reduction is expected to increase with the number of tasks, so it
   seems reasonable to hypothesize that a system with 150,000 tasks
   might see a 20-fold reduction in CPU overhead

 - Torture-test updates

 - Updates that merge RCU's dyntick-idle tracking into context tracking,
   thus reducing the overhead of transitioning to kernel mode from
   either idle or nohz_full userspace execution for kernels that track
   context independently of RCU.

   This is expected to be helpful primarily for kernels built with
   CONFIG_NO_HZ_FULL=y

* tag 'rcu.2022.07.26a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (98 commits)
  rcu: Add irqs-disabled indicator to expedited RCU CPU stall warnings
  rcu: Diagnose extended sync_rcu_do_polled_gp() loops
  rcu: Put panic_on_rcu_stall() after expedited RCU CPU stall warnings
  rcutorture: Test polled expedited grace-period primitives
  rcu: Add polled expedited grace-period primitives
  rcutorture: Verify that polled GP API sees synchronous grace periods
  rcu: Make Tiny RCU grace periods visible to polled APIs
  rcu: Make polled grace-period API account for expedited grace periods
  rcu: Switch polled grace-period APIs to ->gp_seq_polled
  rcu/nocb: Avoid polling when my_rdp->nocb_head_rdp list is empty
  rcu/nocb: Add option to opt rcuo kthreads out of RT priority
  rcu: Add nocb_cb_kthread check to rcu_is_callbacks_kthread()
  rcu/nocb: Add an option to offload all CPUs on boot
  rcu/nocb: Fix NOCB kthreads spawn failure with rcu_nocb_rdp_deoffload() direct call
  rcu/nocb: Invert rcu_state.barrier_mutex VS hotplug lock locking order
  rcu/nocb: Add/del rdp to iterate from rcuog itself
  rcu/tree: Add comment to describe GP-done condition in fqs loop
  rcu: Initialize first_gp_fqs at declaration in rcu_gp_fqs()
  rcu/kvfree: Remove useless monitor_todo flag
  rcu: Cleanup RCU urgency state for offline CPU
  ...
2022-08-02 19:12:45 -07:00
Zhiqiang Liu
59927cbe3f tracing: Use free_trace_buffer() in allocate_trace_buffers()
In allocate_trace_buffers(), if allocating tr->max_buffer
fails, we can directly call free_trace_buffer to free
tr->array_buffer.

Link: https://lkml.kernel.org/r/65f0702d-07f6-08de-2a07-4c50af56a67b@huawei.com

Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-08-02 15:13:19 -04:00
Daniel Bristot de Oliveira
102227b970 rv: Add Runtime Verification (RV) interface
RV is a lightweight (yet rigorous) method that complements classical
exhaustive verification techniques (such as model checking and
theorem proving) with a more practical approach to complex systems.

RV works by analyzing the trace of the system's actual execution,
comparing it against a formal specification of the system behavior.
RV can give precise information on the runtime behavior of the
monitored system while enabling the reaction for unexpected
events, avoiding, for example, the propagation of a failure on
safety-critical systems.

The development of this interface roots in the development of the
paper:

De Oliveira, Daniel Bristot; Cucinotta, Tommaso; De Oliveira, Romulo
Silva. Efficient formal verification for the Linux kernel. In:
International Conference on Software Engineering and Formal Methods.
Springer, Cham, 2019. p. 315-332.

And:

De Oliveira, Daniel Bristot. Automata-based formal analysis
and verification of the real-time Linux kernel. PhD Thesis, 2020.

The RV interface resembles the tracing/ interface on purpose. The current
path for the RV interface is /sys/kernel/tracing/rv/.

It presents these files:

 "available_monitors"
   - List the available monitors, one per line.

   For example:
     # cat available_monitors
     wip
     wwnr

 "enabled_monitors"
   - Lists the enabled monitors, one per line;
   - Writing to it enables a given monitor;
   - Writing a monitor name with a '!' prefix disables it;
   - Truncating the file disables all enabled monitors.

   For example:
     # cat enabled_monitors
     # echo wip > enabled_monitors
     # echo wwnr >> enabled_monitors
     # cat enabled_monitors
     wip
     wwnr
     # echo '!wip' >> enabled_monitors
     # cat enabled_monitors
     wwnr
     # echo > enabled_monitors
     # cat enabled_monitors
     #

   Note that more than one monitor can be enabled concurrently.

 "monitoring_on"
   - It is an on/off general switcher for monitoring. Note
   that it does not disable enabled monitors or detach events,
   but stop the per-entity monitors of monitoring the events
   received from the system. It resembles the "tracing_on" switcher.

 "monitors/"
   Each monitor will have its one directory inside "monitors/". There
   the monitor specific files will be presented.
   The "monitors/" directory resembles the "events" directory on
   tracefs.

   For example:
     # cd monitors/wip/
     # ls
     desc  enable
     # cat desc
     wakeup in preemptive per-cpu testing monitor.
     # cat enable
     0

For further information, see the comments in the header of
kernel/trace/rv/rv.c from this patch.

Link: https://lkml.kernel.org/r/a4bfe038f50cb047bfb343ad0e12b0e646ab308b.1659052063.git.bristot@kernel.org

Cc: Wim Van Sebroeck <wim@linux-watchdog.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Gabriele Paoloni <gpaoloni@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Tao Zhou <tao.zhou@linux.dev>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-07-30 14:01:28 -04:00
Linyu Yuan
95c104c378 tracing: Auto generate event name when creating a group of events
Currently when creating a specific group of trace events,
take kprobe event as example, the user must use the following format:
p:GRP/EVENT [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS],
which means user must enter EVENT name, one example is:

  echo 'p:usb_gadget/config_usb_cfg_link config_usb_cfg_link $arg1' >> kprobe_events

It is not simple if there are too many entries because the event name is
the same as symbol name.

This change allows user to specify no EVENT name, format changed as:

   p:GRP/ [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]

It will generate event name automatically and one example is:

  echo 'p:usb_gadget/ config_usb_cfg_link $arg1' >> kprobe_events.

Link: https://lore.kernel.org/all/1656296348-16111-4-git-send-email-quic_linyyuan@quicinc.com/

Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-07-24 19:11:17 -04:00
Douglas Anderson
495fcec864 tracing: Fix sleeping while atomic in kdb ftdump
If you drop into kdb and type "ftdump" you'll get a sleeping while
atomic warning from memory allocation in trace_find_next_entry().

This appears to have been caused by commit ff895103a8 ("tracing:
Save off entry when peeking at next entry"), which added the
allocation in that path. The problematic commit was already fixed by
commit 8e99cf91b9 ("tracing: Do not allocate buffer in
trace_find_next_entry() in atomic") but that fix missed the kdb case.

The fix here is easy: just move the assignment of the static buffer to
the place where it should have been to begin with:
trace_init_global_iter(). That function is called in two places, once
is right before the assignment of the static buffer added by the
previous fix and once is in kdb.

Note that it appears that there's a second static buffer that we need
to assign that was added in commit efbbdaa22b ("tracing: Show real
address for trace event arguments"), so we'll move that too.

Link: https://lkml.kernel.org/r/20220708170919.1.I75844e5038d9425add2ad853a608cb44bb39df40@changeid

Fixes: ff895103a8 ("tracing: Save off entry when peeking at next entry")
Fixes: efbbdaa22b ("tracing: Show real address for trace event arguments")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-07-12 16:35:58 -04:00
Frederic Weisbecker
493c182282 context_tracking: Take NMI eqs entrypoints over RCU
The RCU dynticks counter is going to be merged into the context tracking
subsystem. Prepare with moving the NMI extended quiescent states
entrypoints to context tracking. For now those are dumb redirection to
existing RCU calls.

Acked-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Cc: Uladzislau Rezki <uladzislau.rezki@sony.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Nicolas Saenz Julienne <nsaenz@kernel.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Cc: Yu Liao <liaoyu15@huawei.com>
Cc: Phil Auld <pauld@redhat.com>
Cc: Paul Gortmaker<paul.gortmaker@windriver.com>
Cc: Alex Belits <abelits@marvell.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
2022-07-05 13:32:59 -07:00
Frederic Weisbecker
6f0e6c1598 context_tracking: Take IRQ eqs entrypoints over RCU
The RCU dynticks counter is going to be merged into the context tracking
subsystem. Prepare with moving the IRQ extended quiescent states
entrypoints to context tracking. For now those are dumb redirection to
existing RCU calls.

[ paulmck: Apply Stephen Rothwell feedback from -next. ]
[ paulmck: Apply Nathan Chancellor feedback. ]

Acked-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Cc: Uladzislau Rezki <uladzislau.rezki@sony.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Nicolas Saenz Julienne <nsaenz@kernel.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Cc: Yu Liao <liaoyu15@huawei.com>
Cc: Phil Auld <pauld@redhat.com>
Cc: Paul Gortmaker<paul.gortmaker@windriver.com>
Cc: Alex Belits <abelits@marvell.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
2022-07-05 13:32:59 -07:00
sunliming
f4b0d31809 tracing: Simplify conditional compilation code in tracing_set_tracer()
Two conditional compilation directives "#ifdef CONFIG_TRACER_MAX_TRACE"
are used consecutively, and no other code in between. Simplify conditional
the compilation code and only use one "#ifdef CONFIG_TRACER_MAX_TRACE".

Link: https://lkml.kernel.org/r/20220602140613.545069-1-sunliming@kylinos.cn

Signed-off-by: sunliming <sunliming@kylinos.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-06-17 18:42:17 -04:00
Linus Torvalds
76bfd3de34 tracing updates for 5.19:
- The majority of the changes are for fixes and clean ups.
 
 Noticeable changes:
 
 - Rework trace event triggers code to be easier to interact with.
 
 - Support for embedding bootconfig with the kernel (as suppose to having it
   embedded in initram). This is useful for embedded boards without initram
   disks.
 
 - Speed up boot by parallelizing the creation of tracefs files.
 
 - Allow absolute ring buffer timestamps handle timestamps that use more than
   59 bits.
 
 - Added new tracing clock "TAI" (International Atomic Time)
 
 - Have weak functions show up in available_filter_function list as:
    __ftrace_invalid_address___<invalid-offset>
   instead of using the name of the function before it.
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 =+nDD
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Merge tag 'trace-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "The majority of the changes are for fixes and clean ups.

  Notable changes:

   - Rework trace event triggers code to be easier to interact with.

   - Support for embedding bootconfig with the kernel (as suppose to
     having it embedded in initram). This is useful for embedded boards
     without initram disks.

   - Speed up boot by parallelizing the creation of tracefs files.

   - Allow absolute ring buffer timestamps handle timestamps that use
     more than 59 bits.

   - Added new tracing clock "TAI" (International Atomic Time)

   - Have weak functions show up in available_filter_function list as:
     __ftrace_invalid_address___<invalid-offset> instead of using the
     name of the function before it"

* tag 'trace-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (52 commits)
  ftrace: Add FTRACE_MCOUNT_MAX_OFFSET to avoid adding weak function
  tracing: Fix comments for event_trigger_separate_filter()
  x86/traceponit: Fix comment about irq vector tracepoints
  x86,tracing: Remove unused headers
  ftrace: Clean up hash direct_functions on register failures
  tracing: Fix comments of create_filter()
  tracing: Disable kcov on trace_preemptirq.c
  tracing: Initialize integer variable to prevent garbage return value
  ftrace: Fix typo in comment
  ftrace: Remove return value of ftrace_arch_modify_*()
  tracing: Cleanup code by removing init "char *name"
  tracing: Change "char *" string form to "char []"
  tracing/timerlat: Do not wakeup the thread if the trace stops at the IRQ
  tracing/timerlat: Print stacktrace in the IRQ handler if needed
  tracing/timerlat: Notify IRQ new max latency only if stop tracing is set
  kprobes: Fix build errors with CONFIG_KRETPROBES=n
  tracing: Fix return value of trace_pid_write()
  tracing: Fix potential double free in create_var_ref()
  tracing: Use strim() to remove whitespace instead of doing it manually
  ftrace: Deal with error return code of the ftrace_process_locs() function
  ...
2022-05-29 10:31:36 -07:00
liqiong
2decd16f47 tracing: Cleanup code by removing init "char *name"
The pointer is assigned to "type->name" anyway. no need to
initialize with "preemption".

Link: https://lkml.kernel.org/r/20220513075221.26275-1-liqiong@nfschina.com

Signed-off-by: liqiong <liqiong@nfschina.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-05-26 21:13:00 -04:00
liqiong
2d601b9864 tracing: Change "char *" string form to "char []"
The "char []" string form declares a single variable. It is better
than "char *" which creates two variables in the final assembly.

Link: https://lkml.kernel.org/r/20220512143230.28796-1-liqiong@nfschina.com

Signed-off-by: liqiong <liqiong@nfschina.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-05-26 21:13:00 -04:00
Wonhyuk Yang
b27f266f74 tracing: Fix return value of trace_pid_write()
Setting set_event_pid with trailing whitespace lead to endless write
system calls like below.

    $ strace echo "123 " > /sys/kernel/debug/tracing/set_event_pid
    execve("/usr/bin/echo", ["echo", "123 "], ...) = 0
    ...
    write(1, "123 \n", 5)                   = 4
    write(1, "\n", 1)                       = 0
    write(1, "\n", 1)                       = 0
    write(1, "\n", 1)                       = 0
    write(1, "\n", 1)                       = 0
    write(1, "\n", 1)                       = 0
    ....

This is because, the result of trace_get_user's are not returned when it
read at least one pid. To fix it, update read variable even if
parser->idx == 0.

The result of applied patch is below.

    $ strace echo "123 " > /sys/kernel/debug/tracing/set_event_pid
    execve("/usr/bin/echo", ["echo", "123 "], ...) = 0
    ...
    write(1, "123 \n", 5)                   = 5
    close(1)                                = 0

Link: https://lkml.kernel.org/r/20220503050546.288911-1-vvghjk1234@gmail.com

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Baik Song An <bsahn@etri.re.kr>
Cc: Hong Yeon Kim <kimhy@etri.re.kr>
Cc: Taeung Song <taeung@reallinux.co.kr>
Cc: linuxgeek@linuxgeek.io
Cc: stable@vger.kernel.org
Fixes: 4909010788 ("tracing: Add set_event_pid directory for future use")
Signed-off-by: Wonhyuk Yang <vvghjk1234@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-05-26 21:12:59 -04:00
Yuntao Wang
cb24693d94 tracing: Use strim() to remove whitespace instead of doing it manually
The tracing_set_trace_write() function just removes the trailing whitespace
from the user supplied tracer name, but the leading whitespace should also
be removed.

In addition, if the user supplied tracer name contains only a few
whitespace characters, the first one will not be removed using the current
method, which results it a single whitespace character left in the buf.

To fix all of these issues, we use strim() to correctly remove both the
leading and trailing whitespace.

Link: https://lkml.kernel.org/r/20220121095623.1826679-1-ytcoode@gmail.com

Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-05-26 21:12:59 -04:00
Kurt Kanzenbach
c575afe21c tracing: Introduce trace clock tai
A fast/NMI safe accessor for CLOCK_TAI has been introduced.
Use it for adding the additional trace clock "tai".

Link: https://lkml.kernel.org/r/20220414091805.89667-3-kurt@linutronix.de

Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-27 17:19:30 -04:00
Mark-PK Tsai
6621a70046 tracing: make tracer_init_tracefs initcall asynchronous
Move trace_eval_init() to subsys_initcall to make it start
earlier.
And to avoid tracer_init_tracefs being blocked by
trace_event_sem which trace_eval_init() hold [1],
queue tracer_init_tracefs() to eval_map_wq to let
the two works being executed sequentially.

It can speed up the initialization of kernel as result
of making tracer_init_tracefs asynchronous.

On my arm64 platform, it reduce ~20ms of 125ms which total
time do_initcalls spend.

Link: https://lkml.kernel.org/r/20220426122407.17042-3-mark-pk.tsai@mediatek.com

[1]: https://lore.kernel.org/r/68d7b3327052757d0cd6359a6c9015a85b437232.camel@pengutronix.de
Signed-off-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-26 17:58:52 -04:00
Mark-PK Tsai
ef9188bcc6 tracing: Avoid adding tracer option before update_tracer_options
To prepare for support asynchronous tracer_init_tracefs initcall,
avoid calling create_trace_option_files before __update_tracer_options.
Otherwise, create_trace_option_files will show warning because
some tracers in trace_types list are already in tr->topts.

For example, hwlat_tracer call register_tracer in late_initcall,
and global_trace.dir is already created in tracing_init_dentry,
hwlat_tracer will be put into tr->topts.
Then if the __update_tracer_options is executed after hwlat_tracer
registered, create_trace_option_files find that hwlat_tracer is
already in tr->topts.

Link: https://lkml.kernel.org/r/20220426122407.17042-2-mark-pk.tsai@mediatek.com

Link: https://lore.kernel.org/lkml/20220322133339.GA32582@xsang-OptiPlex-9020/
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-26 17:58:52 -04:00
Jun Miao
12025abdc8 tracing: Fix sleeping function called from invalid context on RT kernel
When setting bootparams="trace_event=initcall:initcall_start tp_printk=1" in the
cmdline, the output_printk() was called, and the spin_lock_irqsave() was called in the
atomic and irq disable interrupt context suitation. On the PREEMPT_RT kernel,
these locks are replaced with sleepable rt-spinlock, so the stack calltrace will
be triggered.
Fix it by raw_spin_lock_irqsave when PREEMPT_RT and "trace_event=initcall:initcall_start
tp_printk=1" enabled.

 BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46
 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper/0
 preempt_count: 2, expected: 0
 RCU nest depth: 0, expected: 0
 Preemption disabled at:
 [<ffffffff8992303e>] try_to_wake_up+0x7e/0xba0
 CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.17.1-rt17+ #19 34c5812404187a875f32bee7977f7367f9679ea7
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
 Call Trace:
  <TASK>
  dump_stack_lvl+0x60/0x8c
  dump_stack+0x10/0x12
  __might_resched.cold+0x11d/0x155
  rt_spin_lock+0x40/0x70
  trace_event_buffer_commit+0x2fa/0x4c0
  ? map_vsyscall+0x93/0x93
  trace_event_raw_event_initcall_start+0xbe/0x110
  ? perf_trace_initcall_finish+0x210/0x210
  ? probe_sched_wakeup+0x34/0x40
  ? ttwu_do_wakeup+0xda/0x310
  ? trace_hardirqs_on+0x35/0x170
  ? map_vsyscall+0x93/0x93
  do_one_initcall+0x217/0x3c0
  ? trace_event_raw_event_initcall_level+0x170/0x170
  ? push_cpu_stop+0x400/0x400
  ? cblist_init_generic+0x241/0x290
  kernel_init_freeable+0x1ac/0x347
  ? _raw_spin_unlock_irq+0x65/0x80
  ? rest_init+0xf0/0xf0
  kernel_init+0x1e/0x150
  ret_from_fork+0x22/0x30
  </TASK>

Link: https://lkml.kernel.org/r/20220419013910.894370-1-jun.miao@intel.com

Signed-off-by: Jun Miao <jun.miao@intel.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-26 17:58:52 -04:00
Jiapeng Chong
3b57d8477c tracing: Fix kernel-doc
Fix the following W=1 kernel warnings:

kernel/trace/trace.c:1181: warning: expecting prototype for
tracing_snapshot_cond_data(). Prototype was for
tracing_cond_snapshot_data() instead.

Link: https://lkml.kernel.org/r/20220218100849.122038-1-jiapeng.chong@linux.alibaba.com

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-26 17:58:51 -04:00
Oscar Shiang
cf2adec747 tracing: Fix inconsistent style of mini-HOWTO
Each description should start with a hyphen and a space. Insert
spaces to fix it.

Link: https://lkml.kernel.org/r/TYCP286MB19130AA4A9C6FC5A8793DED2A1359@TYCP286MB1913.JPNP286.PROD.OUTLOOK.COM

Signed-off-by: Oscar Shiang <oscar0225@livemail.tw>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-26 17:58:51 -04:00
Valentin Schneider
089c02ae27 ftrace: Use preemption model accessors for trace header printout
Per PREEMPT_DYNAMIC, checking CONFIG_PREEMPT doesn't tell you the actual
preemption model of the live kernel. Use the newly-introduced accessors
instead.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20211112185203.280040-5-valentin.schneider@arm.com
2022-04-05 10:24:42 +02:00