James Clark a3486ef99a 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 12:56:15 +01:00
..
bpf	bpf: Use VM_MAP instead of VM_ALLOC for ringbuf	2022-02-08 18:34:11 +01:00
cgroup	cgroup/cpuset: Fix "suspicious RCU usage" lockdep warning	2022-02-08 18:34:14 +01:00
configs	drivers/char: remove /dev/kmem for good	2021-05-07 00:26:34 -07:00
debug	kdb: Adopt scheduler's task classification	2021-11-18 19:17:06 +01:00
dma	dma/pool: create dma atomic pool only if dma zone has managed pages	2022-01-27 11:03:00 +01:00
entry	signal: Replace force_fatal_sig with force_exit_sig when in doubt	2021-11-25 09:49:07 +01:00
events	perf: Always wake the parent event	2022-02-16 12:56:15 +01:00
gcov	Kconfig: Introduce ARCH_WANTS_NO_INSTR and CC_HAS_NO_PROFILE_FN_ATTR	2021-06-22 11:07:18 -07:00
irq	PCI/MSI: Move non-mask check back into low level accessors	2021-11-18 19:17:14 +01:00
kcsan	LKMM updates:	2021-09-02 13:00:15 -07:00
livepatch	livepatch: Replace deprecated CPU-hotplug functions.	2021-08-19 12:00:24 +02:00
locking	locking/rtmutex: Fix incorrect condition in rtmutex_spin_on_owner()	2021-12-22 09:32:48 +01:00
power	PM: hibernate: Remove register_nosave_region_late()	2022-02-16 12:56:15 +01:00
printk	printk: restore flushing of NMI buffers on remote CPUs after NMI backtraces	2021-11-25 09:48:45 +01:00
rcu	rcu: Tighten rcu_advance_cbs_nowake() checks	2022-01-29 10:58:25 +01:00
sched	sched: Avoid double preemption in __cond_resched_*lock*()	2022-02-16 12:56:11 +01:00
time	clocksource: Avoid accidental unstable marking of clocksources	2022-01-27 11:04:08 +01:00
trace	tracing: Propagate is_signed to expression	2022-02-16 12:56:08 +01:00
.gitignore	.gitignore: prefix local generated files with a slash	2021-05-02 00:43:35 +09:00
acct.c	kernel/acct.c: use dedicated helper to access rlimit values	2021-09-08 11:50:26 -07:00
async.c	kernel/async.c: remove async_unregister_domain()	2021-05-07 00:26:33 -07:00
audit.c	audit: improve audit queue handling when "audit=1" on cmdline	2022-02-08 18:34:03 +01:00
audit.h	audit: add header protection to kernel/audit.h	2021-07-19 22:38:24 -04:00
audit_fsnotify.c
audit_tree.c	audit: move put_tree() to avoid trim_trees refcount underflow and UAF	2021-08-24 18:52:36 -04:00
audit_watch.c
auditfilter.c
auditsc.c	audit: fix possible null-pointer dereference in audit_filter_rules	2021-10-18 18:27:47 -04:00
backtracetest.c
bounds.c
capability.c
cfi.c	cfi: Use rcu_read_{un}lock_sched_notrace	2021-08-11 13:11:12 -07:00
compat.c	arch: remove compat_alloc_user_space	2021-09-08 15:32:35 -07:00
configs.c
context_tracking.c
cpu.c	sched/scs: Reset task stack state in bringup_cpu()	2021-12-01 09:04:54 +01:00
cpu_pm.c	PM: cpu: Make notifier chain use a raw_spinlock_t	2021-08-16 18:55:32 +02:00
crash_core.c	kernel/crash_core: suppress unknown crashkernel parameter warning	2021-12-29 12:28:49 +01:00
crash_dump.c
cred.c	ucounts: Move get_ucounts from cred_alloc_blank to key_change_session_keyring	2021-10-20 10:34:20 -05:00
delayacct.c	delayacct: Add sysctl to enable at runtime	2021-05-12 11:43:25 +02:00
dma.c
exec_domain.c
exit.c	io_uring: remove files pointer in cancellation functions	2021-08-23 13:10:37 -06:00
extable.c
fail_function.c
fork.c	posix-cpu-timers: Clear task::posix_cputimers_work in copy_process()	2021-11-18 19:17:14 +01:00
freezer.c	sched: Add get_current_state()	2021-06-18 11:43:08 +02:00
futex.c	futex: Remove unused variable 'vpid' in futex_proxy_trylock_atomic()	2021-09-03 23:00:22 +02:00
gen_kheaders.sh	kbuild: clean up ${quiet} checks in shell scripts	2021-05-27 04:01:50 +09:00
groups.c
hung_task.c	Merge branch 'akpm' (patches from Andrew)	2021-07-02 12:08:10 -07:00
iomem.c
irq_work.c	irq_work: Make irq_work_queue() NMI-safe again	2021-06-10 10:00:08 +02:00
jump_label.c	jump_label: Fix jump_label_text_reserved() vs __init	2021-07-05 10:46:20 +02:00
kallsyms.c	module: add printk formats to add module build ID to stacktraces	2021-07-08 11:48:22 -07:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks	locking/rwlock: Provide RT variant	2021-08-17 17:50:51 +02:00
Kconfig.preempt	sched/core: Disable CONFIG_SCHED_CORE by default	2021-06-28 22:43:05 +02:00
kcov.c
kexec.c	kexec: avoid compat_alloc_user_space	2021-09-08 15:32:34 -07:00
kexec_core.c	Merge branch 'rework/printk_safe-removal' into for-linus	2021-08-30 16:36:10 +02:00
kexec_elf.c
kexec_file.c	kernel: kexec_file: fix error return code of kexec_calculate_store_digests()	2021-05-07 00:26:32 -07:00
kexec_internal.h
kheaders.c
kmod.c	modules: add CONFIG_MODPROBE_PATH	2021-05-07 00:26:33 -07:00
kprobes.c	kprobes: Limit max data_size of the kretprobe instances	2021-12-08 09:04:41 +01:00
ksysfs.c
kthread.c	Merge branch 'akpm' (patches from Andrew)	2021-06-29 17:29:11 -07:00
latencytop.c
Makefile	kbuild: update config_data.gz only when the content of .config is changed	2021-05-02 00:43:35 +09:00
module-internal.h
module.c	module: fix clang CFI with MODULE_UNLOAD=n	2021-09-28 12:56:26 +02:00
module_signature.c
module_signing.c
notifier.c	notifier: Remove atomic_notifier_call_chain_robust()	2021-08-16 18:55:32 +02:00
nsproxy.c	memcg: enable accounting for new namesapces and struct nsproxy	2021-09-03 09:58:12 -07:00
padata.c	padata: Remove repeated verbose license text	2021-08-27 16:30:18 +08:00
panic.c	Merge branch 'rework/printk_safe-removal' into for-linus	2021-08-30 16:36:10 +02:00
params.c	params: lift param_set_uint_minmax to common code	2021-08-16 14:42:22 +02:00
pid.c	kernel/pid.c: implement additional checks upon pidfd_create() parameters	2021-08-10 12:53:07 +02:00
pid_namespace.c	memcg: enable accounting for new namesapces and struct nsproxy	2021-09-03 09:58:12 -07:00
profile.c	profiling: fix shift-out-of-bounds bugs	2021-09-08 11:50:26 -07:00
ptrace.c	sched: Change task_struct::state	2021-06-18 11:43:09 +02:00
range.c
reboot.c	reboot: Add hardware protection power-off	2021-06-21 13:08:36 +01:00
regset.c
relay.c
resource.c	kernel/resource: fix return code check in __request_free_mem_region	2021-05-14 19:41:32 -07:00
resource_kunit.c
rseq.c	KVM: rseq: Update rseq when processing NOTIFY_RESUME on xfer to KVM guest	2021-09-22 10:24:01 -04:00
scftorture.c	scftorture: Avoid NULL pointer exception on early exit	2021-07-27 11:39:30 -07:00
scs.c	scs: Release kasan vmalloc poison in scs_free process	2021-11-18 19:16:29 +01:00
seccomp.c	Merge branch 'exit-cleanups-for-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace	2021-09-01 14:52:05 -07:00
signal.c	signal: Replace force_fatal_sig with force_exit_sig when in doubt	2021-11-25 09:49:07 +01:00
smp.c	smp: Fix all kernel-doc warnings	2021-08-11 14:47:16 +02:00
smpboot.c	smpboot: Replace deprecated CPU-hotplug functions.	2021-08-10 14:57:42 +02:00
smpboot.h
softirq.c	genirq: Change force_irqthreads to a static key	2021-08-10 22:50:07 +02:00
stackleak.c
stacktrace.c
static_call.c	static_call: Fix static_call_text_reserved() vs __init	2021-07-05 10:46:33 +02:00
stop_machine.c
sys.c	Merge branch 'akpm' (patches from Andrew)	2021-09-08 12:55:35 -07:00
sys_ni.c	compat: remove some compat entry points	2021-09-08 15:32:35 -07:00
sysctl-test.c	kernel/sysctl-test: Remove some casts which are no-longer required	2021-06-23 16:41:24 -06:00
sysctl.c	Merge branch 'akpm' (patches from Andrew)	2021-09-03 10:08:28 -07:00
task_work.c	kasan: record task_work_add() call stack	2021-04-30 11:20:42 -07:00
taskstats.c
test_kprobes.c
torture.c	torture: Replace deprecated CPU-hotplug functions.	2021-08-10 10:48:07 -07:00
tracepoint.c	tracepoint: Fix kerneldoc comments	2021-08-16 11:39:51 -04:00
tsacct.c	taskstats: Cleanup the use of task->exit_code	2022-01-27 11:05:35 +01:00
ucount.c	ucount: Make get_ucount a safe get_user replacement	2022-02-01 17:27:00 +01:00
uid16.c
uid16.h
umh.c	kernel/umh.c: fix some spelling mistakes	2021-05-07 00:26:34 -07:00
up.c	A set of locking related fixes and updates:	2021-05-09 13:07:03 -07:00
user-return-notifier.c
user.c	fs/epoll: use a per-cpu counter for user's watches count	2021-09-08 11:50:27 -07:00
user_namespace.c	memcg: enable accounting for new namesapces and struct nsproxy	2021-09-03 09:58:12 -07:00
usermode_driver.c	Merge branch 'work.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2021-07-03 11:41:14 -07:00
utsname.c
utsname_sysctl.c
watch_queue.c
watchdog.c	kernel: watchdog: modify the explanation related to watchdog thread	2021-06-29 10:53:46 -07:00
watchdog_hld.c
workqueue.c	workqueue: Fix unbind_workers() VS wq_worker_running() race	2022-01-16 09:12:41 +01:00
workqueue_internal.h	workqueue: Assign a color to barrier work items	2021-08-17 07:49:10 -10:00