Re: [PATCH v2 1/4] perf/core: check return value of perf_event_read IPI

[David Carrillo-Cisneros]

> > The call to smp_call_function_single in perf_event_read() may fail and,
> > when it does, its error value is the one to return.
> >
> Please also describe the symptoms of the bug - under what circumstances may the
> smp-call fail and how does the user notice?
>
> Thanks,
>
>         Ingo
generic_exec_single only fails if cpu is invalid or not online, which
currently is not supposed to happen. Since perf_event_read's error is
not checked, I guess a WARN_ON_ONCE is needed. I'll post a rebased
version with this change.

Thanks,
David