> > 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
