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| author | Peter Zijlstra <peterz@infradead.org> | 2015-02-19 18:03:11 +0100 |
|---|---|---|
| committer | Sasha Levin <sasha.levin@oracle.com> | 2015-04-16 20:11:43 -0400 |
| commit | f7d84d2b7c3e17b7004a1b4e71c3944bdf5d6cbb (patch) | |
| tree | 337b1062e0363dd72063a386f3f75ecffcb43c0c /kernel | |
| parent | 225d923571dfcb1112d33990d788ef90dd758ea6 (diff) | |
| download | lwn-f7d84d2b7c3e17b7004a1b4e71c3944bdf5d6cbb.tar.gz lwn-f7d84d2b7c3e17b7004a1b4e71c3944bdf5d6cbb.zip | |
perf: Fix irq_work 'tail' recursion
[ Upstream commit d525211f9d1be8b523ec7633f080f2116f5ea536 ]
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>
Cc: <stable@vger.kernel.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: Sasha Levin <sasha.levin@oracle.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/events/core.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 2ab023803945..e631dacdb165 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4412,6 +4412,13 @@ static void perf_pending_event(struct irq_work *entry) { struct perf_event *event = container_of(entry, struct perf_event, pending); + int rctx; + + rctx = perf_swevent_get_recursion_context(); + /* + * If we 'fail' here, that's OK, it means recursion is already disabled + * and we won't recurse 'further'. + */ if (event->pending_disable) { event->pending_disable = 0; @@ -4422,6 +4429,9 @@ static void perf_pending_event(struct irq_work *entry) event->pending_wakeup = 0; perf_event_wakeup(event); } + + if (rctx >= 0) + perf_swevent_put_recursion_context(rctx); } /* |