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>

1 files changed, 8 insertions, 0 deletions

diff --git a/kernel/events/core.c b/kernel/events/core.c
index c09767f7db3..d863b3c057b 100644
--- 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;
 }