mirror of git://git.yoctoproject.org/linux-yocto.git synced 2025-07-19 12:50:21 +02:00

vhost_task: Allow vhost layer to use copy_process

Qemu will create vhost devices in the kernel which perform network, SCSI,
etc IO and management operations from worker threads created by the
kthread API. Because the kthread API does a copy_process on the kthreadd
thread, the vhost layer has to use kthread_use_mm to access the Qemu
thread's memory and cgroup_attach_task_all to add itself to the Qemu
thread's cgroups, and it bypasses the RLIMIT_NPROC limit which can result
in VMs creating more threads than the admin expected.

This patch adds a new struct vhost_task which can be used instead of
kthreads. They allow the vhost layer to use copy_process and inherit
the userspace process's mm and cgroups, the task is accounted for
under the userspace's nproc count and can be seen in its process tree,
and other features like namespaces work and are inherited by default.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

2023-03-23 12:45:36 +01:00

5.2 KiB

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SPDX-License-Identifier: GPL-2.0

Makefile for the linux kernel.

obj-y = fork.o exec_domain.o panic.o
cpu.o exit.o softirq.o resource.o
sysctl.o capability.o ptrace.o user.o
signal.o sys.o umh.o workqueue.o pid.o task_work.o
extable.o params.o
kthread.o sys_ni.o nsproxy.o
notifier.o ksysfs.o cred.o reboot.o
async.o range.o smpboot.o ucount.o regset.o

obj-$(CONFIG_USERMODE_DRIVER) += usermode_driver.o obj-$(CONFIG_MODULES) += kmod.o obj-$(CONFIG_MULTIUSER) += groups.o obj-$(CONFIG_VHOST_TASK) += vhost_task.o

ifdef CONFIG_FUNCTION_TRACER

Do not trace internal ftrace files

CFLAGS_REMOVE_irq_work.o = $(CC_FLAGS_FTRACE) endif

Prevents flicker of uninteresting __do_softirq()/__local_bh_disable_ip()

in coverage traces.

KCOV_INSTRUMENT_softirq.o := n

Avoid KCSAN instrumentation in softirq ("No shared variables, all the data

are CPU local" => assume no data races), to reduce overhead in interrupts.

KCSAN_SANITIZE_softirq.o = n

These are called from save_stack_trace() on slub debug path,

and produce insane amounts of uninteresting coverage.

KCOV_INSTRUMENT_extable.o := n KCOV_INSTRUMENT_stacktrace.o := n

Don't self-instrument.

KCOV_INSTRUMENT_kcov.o := n

If sanitizers detect any issues in kcov, it may lead to recursion

via printk, etc.

KASAN_SANITIZE_kcov.o := n KCSAN_SANITIZE_kcov.o := n UBSAN_SANITIZE_kcov.o := n KMSAN_SANITIZE_kcov.o := n CFLAGS_kcov.o := $(call cc-option, -fno-conserve-stack) -fno-stack-protector

obj-y += sched/ obj-y += locking/ obj-y += power/ obj-y += printk/ obj-y += irq/ obj-y += rcu/ obj-y += livepatch/ obj-y += dma/ obj-y += entry/ obj-$(CONFIG_MODULES) += module/

obj-$(CONFIG_KCMP) += kcmp.o obj-$(CONFIG_FREEZER) += freezer.o obj-$(CONFIG_PROFILING) += profile.o obj-$(CONFIG_STACKTRACE) += stacktrace.o obj-y += time/ obj-$(CONFIG_FUTEX) += futex/ obj-$(CONFIG_GENERIC_ISA_DMA) += dma.o obj-$(CONFIG_SMP) += smp.o ifneq ($(CONFIG_SMP),y) obj-y += up.o endif obj-$(CONFIG_UID16) += uid16.o obj-$(CONFIG_MODULE_SIG_FORMAT) += module_signature.o obj-$(CONFIG_KALLSYMS) += kallsyms.o obj-$(CONFIG_KALLSYMS_SELFTEST) += kallsyms_selftest.o obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o obj-$(CONFIG_CRASH_CORE) += crash_core.o obj-$(CONFIG_KEXEC_CORE) += kexec_core.o obj-$(CONFIG_KEXEC) += kexec.o obj-$(CONFIG_KEXEC_FILE) += kexec_file.o obj-$(CONFIG_KEXEC_ELF) += kexec_elf.o obj-$(CONFIG_BACKTRACE_SELF_TEST) += backtracetest.o obj-$(CONFIG_COMPAT) += compat.o obj-$(CONFIG_CGROUPS) += cgroup/ obj-$(CONFIG_UTS_NS) += utsname.o obj-$(CONFIG_USER_NS) += user_namespace.o obj-$(CONFIG_PID_NS) += pid_namespace.o obj-$(CONFIG_IKCONFIG) += configs.o obj-$(CONFIG_IKHEADERS) += kheaders.o obj-$(CONFIG_SMP) += stop_machine.o obj-$(CONFIG_AUDIT) += audit.o auditfilter.o obj-$(CONFIG_AUDITSYSCALL) += auditsc.o audit_watch.o audit_fsnotify.o audit_tree.o obj-$(CONFIG_GCOV_KERNEL) += gcov/ obj-$(CONFIG_KCOV) += kcov.o obj-$(CONFIG_KPROBES) += kprobes.o obj-$(CONFIG_FAIL_FUNCTION) += fail_function.o obj-$(CONFIG_KGDB) += debug/ obj-$(CONFIG_DETECT_HUNG_TASK) += hung_task.o obj-$(CONFIG_LOCKUP_DETECTOR) += watchdog.o obj-$(CONFIG_HARDLOCKUP_DETECTOR_PERF) += watchdog_hld.o obj-$(CONFIG_SECCOMP) += seccomp.o obj-$(CONFIG_RELAY) += relay.o obj-$(CONFIG_SYSCTL) += utsname_sysctl.o obj-$(CONFIG_TASK_DELAY_ACCT) += delayacct.o obj-$(CONFIG_TASKSTATS) += taskstats.o tsacct.o obj-$(CONFIG_TRACEPOINTS) += tracepoint.o obj-$(CONFIG_LATENCYTOP) += latencytop.o obj-$(CONFIG_FUNCTION_TRACER) += trace/ obj-$(CONFIG_TRACING) += trace/ obj-$(CONFIG_TRACE_CLOCK) += trace/ obj-$(CONFIG_RING_BUFFER) += trace/ obj-$(CONFIG_TRACEPOINTS) += trace/ obj-$(CONFIG_RETHOOK) += trace/ obj-$(CONFIG_IRQ_WORK) += irq_work.o obj-$(CONFIG_CPU_PM) += cpu_pm.o obj-$(CONFIG_BPF) += bpf/ obj-$(CONFIG_KCSAN) += kcsan/ obj-$(CONFIG_SHADOW_CALL_STACK) += scs.o obj-$(CONFIG_HAVE_STATIC_CALL) += static_call.o obj-$(CONFIG_HAVE_STATIC_CALL_INLINE) += static_call_inline.o obj-$(CONFIG_CFI_CLANG) += cfi.o

obj-$(CONFIG_PERF_EVENTS) += events/

obj-$(CONFIG_USER_RETURN_NOTIFIER) += user-return-notifier.o obj-$(CONFIG_PADATA) += padata.o obj-$(CONFIG_CRASH_DUMP) += crash_dump.o obj-$(CONFIG_JUMP_LABEL) += jump_label.o obj-$(CONFIG_CONTEXT_TRACKING) += context_tracking.o obj-$(CONFIG_TORTURE_TEST) += torture.o

obj-$(CONFIG_HAS_IOMEM) += iomem.o obj-$(CONFIG_RSEQ) += rseq.o obj-$(CONFIG_WATCH_QUEUE) += watch_queue.o

obj-$(CONFIG_RESOURCE_KUNIT_TEST) += resource_kunit.o obj-$(CONFIG_SYSCTL_KUNIT_TEST) += sysctl-test.o

CFLAGS_stackleak.o += $(DISABLE_STACKLEAK_PLUGIN) obj-$(CONFIG_GCC_PLUGIN_STACKLEAK) += stackleak.o KASAN_SANITIZE_stackleak.o := n KCSAN_SANITIZE_stackleak.o := n KCOV_INSTRUMENT_stackleak.o := n

obj-$(CONFIG_SCF_TORTURE_TEST) += scftorture.o

$(obj)/configs.o: $(obj)/config_data.gz

targets += config_data config_data.gz $(obj)/config_data.gz: $(obj)/config_data FORCE $(call if_changed,gzip)

filechk_cat = cat $<

$(obj)/config_data: $(KCONFIG_CONFIG) FORCE $(call filechk,cat)

$(obj)/kheaders.o: $(obj)/kheaders_data.tar.xz

quiet_cmd_genikh = CHK $(obj)/kheaders_data.tar.xz cmd_genikh = $(CONFIG_SHELL) $(srctree)/kernel/gen_kheaders.sh $@ $(obj)/kheaders_data.tar.xz: FORCE $(call cmd,genikh)

clean-files := kheaders_data.tar.xz kheaders.md5

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