James Clark d0774cf730 perf: Always wake the parent event ... [ Upstream commit 961c391217 ] When using per-process mode and event inheritance is set to true, forked processes will create a new perf events via inherit_event() -> perf_event_alloc(). But these events will not have ring buffers assigned to them. Any call to wakeup will be dropped if it's called on an event with no ring buffer assigned because that's the object that holds the wakeup list. If the child event is disabled due to a call to perf_aux_output_begin() or perf_aux_output_end(), the wakeup is dropped leaving userspace hanging forever on the poll. Normally the event is explicitly re-enabled by userspace after it wakes up to read the aux data, but in this case it does not get woken up so the event remains disabled. This can be reproduced when using Arm SPE and 'stress' which forks once before running the workload. By looking at the list of aux buffers read, it's apparent that they stop after the fork: perf record -e arm_spe// -vvv -- stress -c 1 With this patch applied they continue to be printed. This behaviour doesn't happen when using systemwide or per-cpu mode. Reported-by: Ruben Ayrapetyan <Ruben.Ayrapetyan@arm.com> Signed-off-by: James Clark <james.clark@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20211206113840.130802-2-james.clark@arm.com Signed-off-by: Sasha Levin <sashal@kernel.org>		2022-02-16 12:54:20 +01:00
..
bpf	bpf: Use VM_MAP instead of VM_ALLOC for ringbuf	2022-02-08 18:30:39 +01:00
cgroup	cgroup/cpuset: Fix "suspicious RCU usage" lockdep warning	2022-02-08 18:30:41 +01:00
configs
debug	kgdb: fix to kill breakpoints on initmem after boot	2021-03-04 11:38:46 +01:00
dma	dma/pool: create dma atomic pool only if dma zone has managed pages	2022-01-27 10:53:44 +01:00
entry	KVM: rseq: Update rseq when processing NOTIFY_RESUME on xfer to KVM guest	2021-10-06 15:55:49 +02:00
events	perf: Always wake the parent event	2022-02-16 12:54:20 +01:00
gcov	gcov: re-fix clang-11+ support	2021-04-14 08:41:58 +02:00
irq	genirq/timings: Fix error return code in irq_timings_test_irqs()	2021-09-15 09:50:29 +02:00
kcsan	kcsan: Fix debugfs initcall return type	2021-05-26 12:06:54 +02:00
livepatch	kernel/: fix repeated words in comments	2020-10-16 11:11:19 -07:00
locking	kernel: delete repeated words in comments	2022-02-01 17:25:45 +01:00
power	PM: hibernate: Remove register_nosave_region_late()	2022-02-16 12:54:20 +01:00
printk	printk/console: Allow to disable console output by using console="" or console=null	2021-11-12 14:58:33 +01:00
rcu	rcu: Tighten rcu_advance_cbs_nowake() checks	2022-01-29 10:26:11 +01:00
sched	psi: Fix uaf issue when psi trigger is destroyed while being polled	2022-02-05 12:37:55 +01:00
time	clocksource: Avoid accidental unstable marking of clocksources	2022-01-27 10:54:06 +01:00
trace	tracing: Propagate is_signed to expression	2022-02-16 12:54:17 +01:00
.gitignore	kbuild: update config_data.gz only when the content of .config is changed	2021-05-11 14:47:37 +02:00
acct.c	kernel: acct.c: fix some kernel-doc nits	2020-10-16 11:11:19 -07:00
async.c
audit.c	audit: improve audit queue handling when "audit=1" on cmdline	2022-02-08 18:30:34 +01:00
audit.h
audit_fsnotify.c	fsnotify: generalize handle_inode_event()	2020-12-30 11:54:18 +01:00
audit_tree.c	audit: move put_tree() to avoid trim_trees refcount underflow and UAF	2021-09-03 10:09:31 +02:00
audit_watch.c	fsnotify: generalize handle_inode_event()	2020-12-30 11:54:18 +01:00
auditfilter.c
auditsc.c	audit: fix possible null-pointer dereference in audit_filter_rules	2021-10-27 09:56:52 +02:00
backtracetest.c
bounds.c
capability.c	LSM: Signal to SafeSetID when setting group IDs	2020-10-13 09:17:34 -07:00
compat.c
configs.c
context_tracking.c
cpu.c	sched/scs: Reset task stack state in bringup_cpu()	2021-12-01 09:19:08 +01:00
cpu_pm.c	PM: cpu: Make notifier chain use a raw_spinlock_t	2021-09-15 09:50:40 +02:00
crash_core.c	crash_core, vmcoreinfo: append 'SECTION_SIZE_BITS' to vmcoreinfo	2021-06-23 14:42:52 +02:00
crash_dump.c
cred.c	Revert "Add a reference to ucounts for each cred"	2021-09-08 08:49:00 +02:00
delayacct.c
dma.c
exec_domain.c
exit.c	kernel/io_uring: cancel io_uring before task works	2021-01-30 13:55:18 +01:00
extable.c
fail_function.c	fail_function: Remove a redundant mutex unlock	2020-11-19 11:58:16 -08:00
fork.c	posix-cpu-timers: Clear task::posix_cputimers_work in copy_process()	2021-11-18 14:04:29 +01:00
freezer.c	Revert "kernel: freezer should treat PF_IO_WORKER like PF_KTHREAD for freezing"	2021-04-07 15:00:14 +02:00
futex.c	mm, futex: fix shared futex pgoff on shmem huge page	2021-06-30 08:47:29 -04:00
gen_kheaders.sh
groups.c	LSM: Signal to SafeSetID when setting group IDs	2020-10-13 09:17:34 -07:00
hung_task.c	kernel/hung_task.c: make type annotations consistent	2020-11-02 12:14:19 -08:00
iomem.c
irq_work.c
jump_label.c	jump_label: Fix jump_label_text_reserved() vs __init	2021-07-20 16:05:58 +02:00
kallsyms.c	treewide: Convert macro and uses of __section(foo) to __section("foo")	2020-10-25 14:51:49 -07:00
kcmp.c	exec: Transform exec_update_mutex into a rw_semaphore	2021-01-09 13:46:24 +01:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c
kexec.c	LSM: Introduce kernel_post_load_data() hook	2020-10-05 13:37:03 +02:00
kexec_core.c	kernel: kexec: remove the lock operation of system_transition_mutex	2021-02-03 23:28:37 +01:00
kexec_elf.c
kexec_file.c	kernel: kexec_file: fix error return code of kexec_calculate_store_digests()	2021-05-19 10:13:09 +02:00
kexec_internal.h
kheaders.c
kmod.c
kprobes.c	kprobes: Limit max data_size of the kretprobe instances	2021-12-08 09:03:20 +01:00
ksysfs.c
kthread.c	kthread: Fix PF_KTHREAD vs to_kthread() race	2021-09-03 10:09:31 +02:00
latencytop.c
Makefile	kbuild: update config_data.gz only when the content of .config is changed	2021-05-11 14:47:37 +02:00
module-internal.h
module.c	module: limit enabling module.sig_enforce	2021-06-30 08:47:15 -04:00
module_signature.c	module: harden ELF info handling	2021-03-25 09:04:11 +01:00
module_signing.c	module: harden ELF info handling	2021-03-25 09:04:11 +01:00
notifier.c
nsproxy.c
padata.c
panic.c	panic: don't dump stack twice on warn	2020-11-14 11:26:04 -08:00
params.c	params: Replace zero-length array with flexible-array member	2020-10-29 17:22:59 -05:00
pid.c	exec: Transform exec_update_mutex into a rw_semaphore	2021-01-09 13:46:24 +01:00
pid_namespace.c	memcg: enable accounting for pids in nested pid namespaces	2021-09-18 13:40:36 +02:00
profile.c	profiling: fix shift-out-of-bounds bugs	2021-09-26 14:08:58 +02:00
ptrace.c	ptrace: make ptrace() fail if the tracee changed its pid unexpectedly	2021-05-26 12:06:49 +02:00
range.c	kernel.h: split out min()/max() et al. helpers	2020-10-16 11:11:19 -07:00
reboot.c	reboot: fix overflow parsing reboot cpu number	2020-11-14 11:26:03 -08:00
regset.c
relay.c	kernel/relay.c: drop unneeded initialization	2020-10-16 11:11:22 -07:00
resource.c	kernel/resource: make walk_mem_res() find all busy IORESOURCE_MEM resources	2021-05-19 10:13:09 +02:00
rseq.c	KVM: rseq: Update rseq when processing NOTIFY_RESUME on xfer to KVM guest	2021-10-06 15:55:49 +02:00
scftorture.c
scs.c
seccomp.c	seccomp: Fix setting loaded filter count during TSYNC	2021-08-18 08:59:06 +02:00
signal.c	signal: Remove the bogus sigkill_pending in ptrace_stop	2021-11-18 14:03:47 +01:00
smp.c	smp: Fix smp_call_function_single_async prototype	2021-05-14 09:50:46 +02:00
smpboot.c	sched/core: Initialize the idle task with preemption disabled	2021-07-14 16:55:50 +02:00
smpboot.h
softirq.c
stackleak.c	stackleak: let stack_erasing_sysctl take a kernel pointer buffer	2020-09-19 13:13:39 -07:00
stacktrace.c	stacktrace: Remove reliable argument from arch_stack_walk() callback	2020-09-18 14:24:16 +01:00
static_call.c	static_call: Fix unused variable warn w/o MODULE	2021-09-08 08:49:00 +02:00
stop_machine.c	stop_machine, rcu: Mark functions as notrace	2020-10-26 12:12:27 +01:00
sys.c	prctl: allow to setup brk for et_dyn executables	2021-09-26 14:08:57 +02:00
sys_ni.c	mm/madvise: introduce process_madvise() syscall: an external memory hinting API	2020-10-18 09:27:10 -07:00
sysctl-test.c
sysctl.c	bpf: Add kconfig knob for disabling unpriv bpf by default	2022-01-05 12:40:34 +01:00
task_work.c	task_work: cleanup notification modes	2020-10-17 15:05:30 -06:00
taskstats.c	taskstats: move specifying netlink policy back to ops	2020-10-02 19:11:12 -07:00
test_kprobes.c
torture.c
tracepoint.c	tracepoint: Use rcu get state and cond sync for static call updates	2021-09-03 10:09:30 +02:00
tsacct.c	taskstats: Cleanup the use of task->exit_code	2022-01-27 10:54:33 +01:00
ucount.c	Revert "Add a reference to ucounts for each cred"	2021-09-08 08:49:00 +02:00
uid16.c
uid16.h
umh.c	usermodehelper: reset umask to default before executing user process	2020-10-06 10:31:52 -07:00
up.c	smp: Fix smp_call_function_single_async prototype	2021-05-14 09:50:46 +02:00
user-return-notifier.c
user.c
user_namespace.c	Revert "Add a reference to ucounts for each cred"	2021-09-08 08:49:00 +02:00
usermode_driver.c	bpf: Fix umd memory leak in copy_process()	2021-03-30 14:32:03 +02:00
utsname.c
utsname_sysctl.c
watch_queue.c
watchdog.c	watchdog: fix barriers when printing backtraces from all CPUs	2021-05-19 10:13:00 +02:00
watchdog_hld.c
workqueue.c	workqueue: Fix unbind_workers() VS wq_worker_running() race	2022-01-16 09:14:22 +01:00
workqueue_internal.h