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git.kernel.org/linux-stable/linux-4.20.y
linux-imx/kernel
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Martin KaFai Lau 1038213107 bpf: Fix syscall's stackmap lookup potential deadlock 
[ Upstream commit 7c4cd051ad ]

The map_lookup_elem used to not acquiring spinlock
in order to optimize the reader.

It was true until commit 557c0c6e7d ("bpf: convert stackmap to pre-allocation")
The syscall's map_lookup_elem(stackmap) calls bpf_stackmap_copy().
bpf_stackmap_copy() may find the elem no longer needed after the copy is done.
If that is the case, pcpu_freelist_push() saves this elem for reuse later.
This push requires a spinlock.

If a tracing bpf_prog got run in the middle of the syscall's
map_lookup_elem(stackmap) and this tracing bpf_prog is calling
bpf_get_stackid(stackmap) which also requires the same pcpu_freelist's
spinlock, it may end up with a dead lock situation as reported by
Eric Dumazet in https://patchwork.ozlabs.org/patch/1030266/

The situation is the same as the syscall's map_update_elem() which
needs to acquire the pcpu_freelist's spinlock and could race
with tracing bpf_prog.  Hence, this patch fixes it by protecting
bpf_stackmap_copy() with this_cpu_inc(bpf_prog_active)
to prevent tracing bpf_prog from running.

A later syscall's map_lookup_elem commit f1a2e44a3a ("bpf: add queue and stack maps")
also acquires a spinlock and races with tracing bpf_prog similarly.
Hence, this patch is forward looking and protects the majority
of the map lookups.  bpf_map_offload_lookup_elem() is the exception
since it is for network bpf_prog only (i.e. never called by tracing
bpf_prog).

Fixes: 557c0c6e7d ("bpf: convert stackmap to pre-allocation")
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-03-13 14:04:14 -07:00
..
bpf bpf: Fix syscall's stackmap lookup potential deadlock 2019-03-13 14:04:14 -07:00
cgroup cgroup: fix parsing empty mount option string 2019-02-12 20:02:29 +01:00
configs kvm_config: add CONFIG_VIRTIO_MENU 2018-10-24 20:55:56 -04:00
debug kdb: Don't back trace on a cpu that didn't round up 2019-02-12 20:02:30 +01:00
dma dma-direct: do not include SME mask in the DMA supported check 2018-12-17 18:02:11 +01:00
events perf core: Fix perf_proc_update_handler() bug 2019-03-13 14:04:00 -07:00
gcov gcov: remove CONFIG_GCOV_FORMAT_AUTODETECT 2018-06-08 18:56:02 +09:00
irq genirq: Make sure the initial affinity is not empty 2019-03-05 17:59:36 +01:00
livepatch Merge branch 'for-4.19/upstream' into for-linus 2018-08-20 18:33:50 +02:00
locking locking/rwsem: Fix (possible) missed wakeup 2019-03-05 17:59:39 +01:00
power memblock: stop using implicit alignment to SMP_CACHE_BYTES 2018-10-31 08:54:16 -07:00
printk mm: remove include/linux/bootmem.h 2018-10-31 08:54:16 -07:00
rcu srcu: Lock srcu_data structure in srcu_gp_start() 2019-01-13 09:24:05 +01:00
sched psi: fix aggregation idle shut-off 2019-03-13 14:04:08 -07:00
time timekeeping: Use proper seqcount initializer 2019-02-12 20:02:14 +01:00
trace bpf: fix potential deadlock in bpf_prog_register 2019-03-13 14:04:14 -07:00
.gitignore
acct.c
async.c
audit_fsnotify.c fsnotify: add fsnotify_add_inode_mark() wrappers 2018-05-18 14:58:22 +02:00
audit_tree.c \n 2018-08-17 09:41:28 -07:00
audit_watch.c audit: fix use-after-free in audit_add_watch 2018-07-18 11:43:36 -04:00
audit.c audit: use ktime_get_coarse_real_ts64() for timestamps 2018-07-17 14:45:08 -04:00
audit.h
auditfilter.c audit: rename FILTER_TYPE to FILTER_EXCLUDE 2018-06-19 10:39:54 -04:00
auditsc.c audit/stable-4.18 PR 20180814 2018-08-15 10:46:54 -07:00
backtracetest.c
bounds.c kbuild: fix kernel/bounds.c 'W=1' warning 2018-10-31 08:54:14 -07:00
capability.c
compat.c y2038: globally rename compat_time to old_time32 2018-08-27 14:48:48 +02:00
configs.c
context_tracking.c
cpu_pm.c
cpu.c cpu/hotplug: Fix "SMT disabled by BIOS" detection for KVM 2019-02-12 20:02:37 +01:00
crash_core.c kernel/crash_core.c: print timestamp using time64_t 2018-08-22 10:52:47 -07:00
crash_dump.c
cred.c
delayacct.c delayacct: track delays from thrashing cache pages 2018-10-26 16:26:32 -07:00
dma.c proc: introduce proc_create_single{,_data} 2018-05-16 07:23:35 +02:00
elfcore.c
exec_domain.c proc: introduce proc_create_single{,_data} 2018-05-16 07:23:35 +02:00
exit.c sched/wait: Fix rcuwait_wake_up() ordering 2019-03-05 17:59:39 +01:00
extable.c
fail_function.c kernel/fail_function.c: remove meaningless null pointer check before debugfs_remove_recursive 2018-10-31 08:54:12 -07:00
fork.c fork, memcg: fix cached_stacks case 2019-01-16 22:03:23 +01:00
freezer.c PM / reboot: Eliminate race between reboot and suspend 2018-08-06 12:35:20 +02:00
futex_compat.c y2038: globally rename compat_time to old_time32 2018-08-27 14:48:48 +02:00
futex.c futex: Fix (possible) missed wakeup 2019-03-05 17:59:39 +01:00
groups.c
hung_task.c kernel/hung_task.c: force console verbose before panic 2019-02-12 20:02:31 +01:00
iomem.c memremap: split devm_memremap_pages() and memremap() infrastructure 2018-05-15 23:08:33 -07:00
irq_work.c
jump_label.c Merge branch 'x86/build' into locking/core, to pick up dependent patches and unify jump-label work 2018-10-16 17:30:11 +02:00
kallsyms.c kallsyms: reduce size a little on 64-bit 2018-09-10 22:54:33 +09:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt kconfig: include kernel/Kconfig.preempt from init/Kconfig 2018-08-02 08:06:54 +09:00
kcov.c kernel/kcov.c: mark write_comp_data() as notrace 2019-02-12 20:02:31 +01:00
kexec_core.c kexec: Allocate decrypted control pages for kdump if SME is enabled 2018-10-06 12:01:51 +02:00
kexec_file.c kernel/kexec_file.c: remove some duplicated includes 2018-11-03 10:09:37 -07:00
kexec_internal.h
kexec.c kexec: add call to LSM hook in original kexec_load syscall 2018-07-16 12:31:57 -07:00
kmod.c
kprobes.c kprobes: Don't call BUG_ON() if there is a kprobe in use on free list 2018-09-12 08:01:16 +02:00
ksysfs.c
kthread.c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-08-13 11:25:07 -07:00
latencytop.c
Makefile x86/entry: Add STACKLEAK erasing the kernel stack at the end of syscalls 2018-09-04 10:35:47 -07:00
memremap.c mm, devm_memremap_pages: add MEMORY_DEVICE_PRIVATE support 2019-01-13 09:24:03 +01:00
module_signing.c modsign: log module name in the event of an error 2018-07-02 11:36:17 +02:00
module-internal.h modsign: log module name in the event of an error 2018-07-02 11:36:17 +02:00
module.c kobject: return error code if writing /sys/.../uevent fails 2019-02-12 20:02:15 +01:00
notifier.c
nsproxy.c
padata.c
panic.c panic: avoid deadlocks in re-entrant console drivers 2019-01-09 17:45:49 +01:00
params.c kernel/params.c: downgrade warning for unsafe parameters 2018-04-11 10:28:37 -07:00
pid_namespace.c signal: Use group_send_sig_info to kill all processes in a pid namespace 2018-09-16 16:08:25 +02:00
pid.c Fix failure path in alloc_pid() 2019-01-13 09:24:05 +01:00
profile.c mm: remove include/linux/bootmem.h 2018-10-31 08:54:16 -07:00
ptrace.c ptrace: Remove unused ptrace_may_access_sched() and MODE_IBRS 2018-11-28 11:57:11 +01:00
range.c
reboot.c kernel/reboot.c: export pm_power_off_prepare 2018-09-11 16:13:24 +01:00
relay.c relay: check return of create_buf_file() properly 2019-03-13 14:04:13 -07:00
resource.c resource/docs: Complete kernel-doc style function documentation 2018-11-07 16:47:47 +01:00
rseq.c rseq: uapi: Declare rseq_cs field as union, update includes 2018-07-10 22:18:52 +02:00
seccomp.c Merge branch 'next-general' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2018-10-24 11:49:35 +01:00
signal.c signal: Restore the stop PTRACE_EVENT_EXIT 2019-02-20 10:29:14 +01:00
smp.c cpu/hotplug: Fix "SMT disabled by BIOS" detection for KVM 2019-02-12 20:02:37 +01:00
smpboot.c smpboot: Remove cpumask from the API 2018-07-03 09:20:44 +02:00
smpboot.h
softirq.c Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-10-25 11:43:47 -07:00
stackleak.c stackleak: Mark stackleak_track_stack() as notrace 2018-12-05 19:31:44 -08:00
stacktrace.c
stop_machine.c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-08-13 11:25:07 -07:00
sys_ni.c Merge branch 'core-rseq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-10 10:17:09 -07:00
sys.c kernel/sys.c: remove duplicated include 2018-09-20 22:01:11 +02:00
sysctl_binary.c staging: irda: remove remaining remants of irda code removal 2018-04-16 11:26:49 +02:00
sysctl.c proc/sysctl: fix return error for proc_doulongvec_minmax() 2019-02-12 20:02:31 +01:00
task_work.c
taskstats.c
test_kprobes.c kprobes: Remove jprobe API implementation 2018-06-21 12:33:05 +02:00
torture.c rcutorture: Check GP completion at stutter end 2018-08-29 09:20:48 -07:00
tracepoint.c tracepoint: Fix tracepoint array element size mismatch 2018-10-17 15:35:29 -04:00
tsacct.c
ucount.c
uid16.c
uid16.h
umh.c umh: Add command line to user mode helpers 2018-10-22 19:37:36 -07:00
up.c smp,cpumask: introduce on_each_cpu_cond_mask 2018-10-09 16:51:11 +02:00
user_namespace.c userns: also map extents in the reverse map to kernel IDs 2018-11-07 23:51:16 -06:00
user-return-notifier.c
user.c userns: use irqsave variant of refcount_dec_and_lock() 2018-08-22 10:52:47 -07:00
utsname_sysctl.c sys: don't hold uts_sem while accessing userspace memory 2018-08-11 02:05:53 -05:00
utsname.c uts: create "struct uts_namespace" from kmem_cache 2018-04-11 10:28:35 -07:00
watchdog_hld.c watchdog: Mark watchdog touch functions as notrace 2018-08-30 12:56:40 +02:00
watchdog.c watchdog: Mark watchdog touch functions as notrace 2018-08-30 12:56:40 +02:00
workqueue_internal.h psi: fix aggregation idle shut-off 2019-03-13 14:04:08 -07:00
workqueue.c psi: fix aggregation idle shut-off 2019-03-13 14:04:08 -07:00