From: Kyle Huey Date: Fri, 12 Apr 2024 01:50:18 +0000 (-0700) Subject: perf/bpf: Allow a BPF program to suppress all sample side effects X-Git-Tag: v6.10-rc1~210^2~7 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c4fcc7d1f41532e878087c7c43f4cf247604d68b;p=thirdparty%2Fkernel%2Flinux.git 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 Signed-off-by: Ingo Molnar Acked-by: Song Liu Acked-by: Jiri Olsa Acked-by: Namhyung Kim Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20240412015019.7060-7-khuey@kylehuey.com --- diff --git a/kernel/events/core.c b/kernel/events/core.c index c6a6936183d5b..2212670cbe9b8 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;