diff options
authorDavid Carrillo-Cisneros <davidcc@google.com>2016-08-17 13:55:04 -0700
committerIngo Molnar <mingo@kernel.org>2016-08-18 10:35:52 +0200
commit71e7bc2bab77e64882c031c2af943c3256c1adb0 (patch)
parent99f5bc9bfa9094e7c264a8e09f9507b391a3d1d1 (diff)
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 <davidcc@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vegard Nossum <vegard.nossum@gmail.com> Cc: Vince Weaver <vincent.weaver@maine.edu> Link: http://lkml.kernel.org/r/1471467307-61171-2-git-send-email-davidcc@google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
1 files changed, 4 insertions, 3 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index a5fc5c8cdfb0..5650f5317e0c 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;