[PATCH v2 2/3] perf/bpf: Allow a bpf program to suppress all sample side effects.

[Kyle Huey <me@xxxxxxxxxxxx>]

Returning zero from a bpf program attached to a perf event already
suppresses any data output. By clearing pending_kill, returning zero from a
bpf program will effectively pretend the sample never happened for all
userspace purposes.

Signed-off-by: Kyle Huey <khuey@xxxxxxxxxxxx>
---
 kernel/events/core.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 19fddfc27a4a..6cda05a4969d 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10421,8 +10421,10 @@ static void bpf_overflow_handler(struct perf_event *event,
 	rcu_read_unlock();
 out:
 	__this_cpu_dec(bpf_prog_active);
-	if (!ret)
+	if (!ret) {
+		event->pending_kill = 0;
 		return;
+	}
 
 	event->orig_overflow_handler(event, data, regs);
 }
-- 
2.34.1