Commit-ID: 71e7bc2bab77e64882c031c2af943c3256c1adb0 Gitweb: http://git.kernel.org/tip/71e7bc2bab77e64882c031c2af943c3256c1adb0 Author: David Carrillo-Cisneros <davi...@google.com> AuthorDate: Wed, 17 Aug 2016 13:55:04 -0700 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Thu, 18 Aug 2016 10:35:52 +0200
perf/core: Check return value of the perf_event_read() IPI The call to smp_call_function_single in perf_event_read() may fail if an invalid or not online CPU index is passed. Warn user if such bug is present and return error. Signed-off-by: David Carrillo-Cisneros <davi...@google.com> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Cc: Alexander Shishkin <alexander.shish...@linux.intel.com> Cc: Arnaldo Carvalho de Melo <a...@redhat.com> Cc: Jiri Olsa <jo...@redhat.com> Cc: Kan Liang <kan.li...@intel.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Paul Turner <p...@google.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Stephane Eranian <eran...@google.com> Cc: Thomas Gleixner <t...@linutronix.de> Cc: Vegard Nossum <vegard.nos...@gmail.com> Cc: Vince Weaver <vincent.wea...@maine.edu> Link: http://lkml.kernel.org/r/1471467307-61171-2-git-send-email-davi...@google.com Signed-off-by: Ingo Molnar <mi...@kernel.org> --- kernel/events/core.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index a5fc5c8..5650f53 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3549,9 +3549,10 @@ static int perf_event_read(struct perf_event *event, bool group) .group = group, .ret = 0, }; - smp_call_function_single(event->oncpu, - __perf_event_read, &data, 1); - ret = data.ret; + ret = smp_call_function_single(event->oncpu, __perf_event_read, &data, 1); + /* The event must have been read from an online CPU: */ + WARN_ON_ONCE(ret); + ret = ret ? : data.ret; } else if (event->state == PERF_EVENT_STATE_INACTIVE) { struct perf_event_context *ctx = event->ctx; unsigned long flags;
