perf: Fix SIGIO handling

Vince noticed that unless we mmap() a buffer, SIGIO gets lost. So
explicitly push the wakeup (including signals) when requested.

Reported-by: Vince Weaver <vweaver1@eecs.utk.edu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@kernel.org>
Link: http://lkml.kernel.org/n/tip-2euus3f3x3dyvdk52cjxw8zu@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/events/core.c b/kernel/events/core.c
index c09767f..d863b3c 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -5028,6 +5028,14 @@ static int __perf_event_overflow(struct perf_event *event, int nmi,
        else
                perf_event_output(event, nmi, data, regs);
 
+       if (event->fasync && event->pending_kill) {
+               if (nmi) {
+                       event->pending_wakeup = 1;
+                       irq_work_queue(&event->pending);
+               } else
+                       perf_event_wakeup(event);
+       }
+
        return ret;
 }