path: root/arch/arm/kernel/perf_event.c
diff options
authorWill Deacon <will.deacon@arm.com>2013-08-07 23:39:41 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2013-08-13 20:21:43 +0100
commitc95eb3184ea1a3a2551df57190c81da695e2144b (patch)
tree7cf42626f642a42d72cce07fe98bdc2afd227d2f /arch/arm/kernel/perf_event.c
parent2ba85e7af4c639d933c9a87a6d7363f2983d5ada (diff)
ARM: 7809/1: perf: fix event validation for software group leaders
It is possible to construct an event group with a software event as a group leader and then subsequently add a hardware event to the group. This results in the event group being validated by adding all members of the group to a fake PMU and attempting to allocate each event on their respective PMU. Unfortunately, for software events wthout a corresponding arm_pmu, this results in a kernel crash attempting to dereference the ->get_event_idx function pointer. This patch fixes the problem by checking explicitly for software events and ignoring those in event validation (since they can always be scheduled). We will probably want to revisit this for 3.12, since the validation checks don't appear to work correctly when dealing with multiple hardware PMUs anyway. Cc: <stable@vger.kernel.org> Reported-by: Vince Weaver <vincent.weaver@maine.edu> Tested-by: Vince Weaver <vincent.weaver@maine.edu> Tested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel/perf_event.c')
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index d9f5cd4e533f..0500f10b5041 100644
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -253,6 +253,9 @@ validate_event(struct pmu_hw_events *hw_events,
struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
struct pmu *leader_pmu = event->group_leader->pmu;
+ if (is_software_event(event))
+ return 1;
if (event->pmu != leader_pmu || event->state < PERF_EVENT_STATE_OFF)
return 1;