The following commit has been merged into the perf/core branch of tip:
Commit-ID: c4fcc7d1f41532e878087c7c43f4cf247604d68b
Gitweb: https://git.kernel.org/tip/c4fcc7d1f41532e878087c7c43f4cf247604d68b
Author: Kyle Huey <me@xxxxxxxxxxxx>
AuthorDate: Thu, 11 Apr 2024 18:50:18 -07:00
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Fri, 12 Apr 2024 11:49:50 +02:00
perf/bpf: Allow a BPF program to suppress all sample side effects
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@xxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Acked-by: Song Liu <song@xxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Acked-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240412015019.7060-7-khuey@xxxxxxxxxxxx
---
kernel/events/core.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index c6a6936..2212670 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -9677,6 +9677,9 @@ static int __perf_event_overflow(struct perf_event *event,
ret = __perf_event_account_interrupt(event, throttle);
+ if (event->prog && !bpf_overflow_handler(event, data, regs))
+ return ret;
+
/*
* XXX event_limit might not quite work as expected on inherited
* events
@@ -9726,8 +9729,7 @@ static int __perf_event_overflow(struct perf_event *event,
irq_work_queue(&event->pending_irq);
}
- if (!(event->prog && !bpf_overflow_handler(event, data, regs)))
- 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;
|