Peter Zijlstra a49a0c95f4 perf: Fix irq_work 'tail' recursion ... commit d525211f9d upstream. Vince reported a watchdog lockup like: [<ffffffff8115e114>] perf_tp_event+0xc4/0x210 [<ffffffff810b4f8a>] perf_trace_lock+0x12a/0x160 [<ffffffff810b7f10>] lock_release+0x130/0x260 [<ffffffff816c7474>] _raw_spin_unlock_irqrestore+0x24/0x40 [<ffffffff8107bb4d>] do_send_sig_info+0x5d/0x80 [<ffffffff811f69df>] send_sigio_to_task+0x12f/0x1a0 [<ffffffff811f71ce>] send_sigio+0xae/0x100 [<ffffffff811f72b7>] kill_fasync+0x97/0xf0 [<ffffffff8115d0b4>] perf_event_wakeup+0xd4/0xf0 [<ffffffff8115d103>] perf_pending_event+0x33/0x60 [<ffffffff8114e3fc>] irq_work_run_list+0x4c/0x80 [<ffffffff8114e448>] irq_work_run+0x18/0x40 [<ffffffff810196af>] smp_trace_irq_work_interrupt+0x3f/0xc0 [<ffffffff816c99bd>] trace_irq_work_interrupt+0x6d/0x80 Which is caused by an irq_work generating new irq_work and therefore not allowing forward progress. This happens because processing the perf irq_work triggers another perf event (tracepoint stuff) which in turn generates an irq_work ad infinitum. Avoid this by raising the recursion counter in the irq_work -- which effectively disables all software events (including tracepoints) from actually triggering again. Reported-by: Vince Weaver <vincent.weaver@maine.edu> Tested-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20150219170311.GH21418@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2015-04-13 14:02:12 +02:00
..
cpu
debug	kdb: fix incorrect counts in KDB summary command output	2015-03-06 14:40:52 -08:00
events	perf: Fix irq_work 'tail' recursion	2015-04-13 14:02:12 +02:00
gcov
irq
power	PM / QoS: remove duplicate call to pm_qos_update_target	2015-03-18 13:22:28 +01:00
sched
time	ntp: Fixup adjtimex freq validation on 32-bit systems	2015-03-06 14:40:52 -08:00
trace	tracing: Fix unmapping loop in tracing_mark_write	2015-03-06 14:40:50 -08:00
.gitignore
acct.c
async.c
audit_tree.c	audit: keep inode pinned	2014-11-21 09:22:52 -08:00
audit_watch.c
audit.c
audit.h
auditfilter.c
auditsc.c
backtracetest.c
bounds.c
capability.c
cgroup_freezer.c
cgroup.c
compat.c
configs.c
context_tracking.c
cpu_pm.c
cpu.c
cpuset.c
crash_dump.c
cred.c
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c	introduce for_each_thread() to replace the buggy while_each_thread()	2014-10-05 14:54:15 -07:00
extable.c
fork.c	perf: fix perf bug in fork()	2014-10-09 12:18:42 -07:00
freezer.c	freezer: Do not freeze tasks killed by OOM killer	2014-11-14 08:47:58 -08:00
futex_compat.c
futex.c
groups.c	userns: Don't allow setgroups until a gid mapping has been setablished	2015-01-08 09:58:16 -08:00
hrtimer.c
hung_task.c
irq_work.c
itimer.c
jump_label.c
kallsyms.c
kcmp.c	kcmp: fix standard comparison bug	2014-10-05 14:54:13 -07:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kexec.c
kmod.c
kprobes.c
ksysfs.c
kthread.c
latencytop.c
lglock.c
lockdep_internals.h
lockdep_proc.c
lockdep_states.h
lockdep.c
Makefile
modsign_certificate.S
modsign_pubkey.c
module_signing.c
module-internal.h
module.c	modules, lock around setting of MODULE_STATE_UNFORMED	2014-11-14 08:47:55 -08:00
mutex-debug.c
mutex-debug.h
mutex.c
mutex.h
notifier.c
nsproxy.c
padata.c
panic.c
params.c
pid_namespace.c
pid.c	exit: pidns: alloc_pid() leaks pid_namespace if child_reaper is exiting	2015-01-08 09:58:17 -08:00
posix-cpu-timers.c
posix-timers.c	posix-timers: Fix stack info leak in timer_create()	2014-11-14 08:48:00 -08:00
printk.c
profile.c
ptrace.c
range.c
rcu.h
rcupdate.c
rcutiny_plugin.h
rcutiny.c
rcutorture.c
rcutree_plugin.h
rcutree_trace.c
rcutree.c
rcutree.h
relay.c
res_counter.c
resource.c
rtmutex_common.h
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c
rtmutex.h
rwsem.c
seccomp.c
semaphore.c
signal.c
smp.c
smpboot.c	smpboot: Add missing get_online_cpus() in smpboot_register_percpu_thread()	2015-02-11 14:48:17 +08:00
smpboot.h
softirq.c
spinlock.c
srcu.c
stacktrace.c
stop_machine.c
sys_ni.c
sys.c
sysctl_binary.c
sysctl.c
task_work.c
taskstats.c
test_kprobes.c
time.c	time: settimeofday: Validate the values of tv from user	2015-01-29 17:40:56 -08:00
timeconst.bc
timer.c
tracepoint.c
tsacct.c
uid16.c	groups: Consolidate the setgroups permission checks	2015-01-08 09:58:16 -08:00
up.c
user_namespace.c	userns: Allow setting gid_maps without privilege when setgroups is disabled	2015-01-08 09:58:17 -08:00
user-return-notifier.c
user.c	userns: Add a knob to disable setgroups on a per user namespace basis	2015-01-08 09:58:16 -08:00
utsname_sysctl.c
utsname.c
wait.c
watchdog.c
workqueue_internal.h
workqueue.c	workqueue: fix hang involving racing cancel[_delayed]_work_sync()'s for PREEMPT_NONE	2015-03-26 15:00:58 +01:00