On Tue, Jul 16, 2024 at 12:25 AM Jiri Olsa <olsajiri@xxxxxxxxx> wrote:
>
> On Mon, Jul 15, 2024 at 09:48:58AM -0700, Kyle Huey wrote:
> > On Mon, Jul 15, 2024 at 9:30 AM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> > >
> > > On Mon, Jul 15, 2024 at 08:19:44AM -0700, Kyle Huey wrote:
> > >
> > > > I think this would probably work but stealing the bit seems far more
> > > > complicated than just gating on perf_event_is_tracing().
> > >
> > > perf_event_is_tracing() is something like 3 branches. It is not a simple
> > > conditional. Combined with that re-load and the wrong return value, this
> > > all wants a cleanup.
> > >
> > > Using that LSB works, it's just that the code aint pretty.
> >
> > Maybe we could gate on !event->tp_event instead. Somebody who is more
> > familiar with this code than me should probably confirm that tp_event
> > being non-null and perf_event_is_tracing() being true are equivalent
> > though.
> >
>
> it looks like that's the case, AFAICS tracepoint/kprobe/uprobe events
> are the only ones having the tp_event pointer set, Masami?
>
> fwiw I tried to run bpf selftests with that and it's fine
Why can't we do the most straightforward thing in this case?
diff --git a/kernel/events/core.c b/kernel/events/core.c
index ab6c4c942f79..cf4645b26c90 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -9707,7 +9707,8 @@ 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))
+ if (event->prog && event->prog->type == BPF_PROG_TYPE_PERF_EVENT &&
+ !bpf_overflow_handler(event, data, regs))
return ret;
>
> jirka
>
