diff options
| author | Drew Richardson <drew.richardson@arm.com> | 2015-07-30 08:27:19 -0700 |
|---|---|---|
| committer | Jon Medhurst <tixy@linaro.org> | 2015-07-31 11:13:11 +0100 |
| commit | 5d841367afb5252f8db7af1b4a765d0837f5921e (patch) | |
| tree | e0056d8672e85759adc6b3ea014cd9e93747832d | |
| parent | 83f711b8f028f2ba6fbd58d49136b33a9fc05c6d (diff) | |
gator: Fix race in perf event setup
Save the result of perf_event_create_kernel_counter to a temporary
location so if it fails the error value will not be seen in __read
and mistakenly used as pointer.
Signed-off-by: Drew Richardson <Drew.Richardson@arm.com>
Signed-off-by: Jon Medhurst <tixy@linaro.org>
| -rw-r--r-- | driver/gator_events_perf_pmu.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/driver/gator_events_perf_pmu.c b/driver/gator_events_perf_pmu.c index d49277d..e62492b 100644 --- a/driver/gator_events_perf_pmu.c +++ b/driver/gator_events_perf_pmu.c @@ -136,6 +136,7 @@ static int gator_events_perf_pmu_online(int **buffer, bool migrate) static void __online_dispatch(int cpu, bool migrate, struct gator_attr *const attr, struct gator_event *const event) { perf_overflow_handler_t handler; + struct perf_event *pevent; event->zero = true; @@ -148,22 +149,22 @@ static void __online_dispatch(int cpu, bool migrate, struct gator_attr *const at handler = dummy_handler; #if LINUX_VERSION_CODE < KERNEL_VERSION(3, 1, 0) - event->pevent = perf_event_create_kernel_counter(event->pevent_attr, cpu, 0, handler); + pevent = perf_event_create_kernel_counter(event->pevent_attr, cpu, 0, handler); #else - event->pevent = perf_event_create_kernel_counter(event->pevent_attr, cpu, 0, handler, 0); + pevent = perf_event_create_kernel_counter(event->pevent_attr, cpu, 0, handler, 0); #endif - if (IS_ERR(event->pevent)) { + if (IS_ERR(pevent)) { pr_err("gator: unable to online a counter on cpu %d\n", cpu); - event->pevent = NULL; return; } - if (event->pevent->state != PERF_EVENT_STATE_ACTIVE) { + if (pevent->state != PERF_EVENT_STATE_ACTIVE) { pr_err("gator: inactive counter on cpu %d\n", cpu); - perf_event_release_kernel(event->pevent); - event->pevent = NULL; + perf_event_release_kernel(pevent); return; } + + event->pevent = pevent; } static void gator_events_perf_pmu_online_dispatch(int cpu, bool migrate) |