Returning zero from a bpf program attached to a perf event already
suppresses any data output. Return early from __perf_event_overflow() in
this case so it will also suppress event_limit accounting, SIGTRAP
generation, and F_ASYNC signalling.
Signed-off-by: Kyle Huey <khuey@kylehuey.com>
Acked-by: Song Liu <song@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
---
kernel/events/core.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 24a718e7eb98..a329bec42c4d 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -9574,6 +9574,11 @@ static int __perf_event_overflow(struct perf_event *event,
ret = __perf_event_account_interrupt(event, throttle);
+#ifdef CONFIG_BPF_SYSCALL
+ if (event->prog && !bpf_overflow_handler(event, data, regs))
+ return ret;
+#endif
+
/*
* XXX event_limit might not quite work as expected on inherited
* events
@@ -9623,10 +9628,7 @@ static int __perf_event_overflow(struct perf_event *event,
irq_work_queue(&event->pending_irq);
}
-#ifdef CONFIG_BPF_SYSCALL
- if (!(event->prog && !bpf_overflow_handler(event, data, regs)))
-#endif
- READ_ONCE(event->overflow_handler)(event, data, regs);
+ READ_ONCE(event->overflow_handler)(event, data, regs);
if (*perf_event_fasync(event) && event->pending_kill) {
event->pending_wakeup = 1;
--
2.34.1