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authorWill Deacon <will.deacon@arm.com>2013-08-07 23:39:41 +0100
committerBen Hutchings <ben@decadent.org.uk>2013-09-10 01:57:23 +0100
commit5fff965ef7b5b2a3715b1a4005e6515716e49305 (patch)
tree67045c9097fee68a83e268f398f6382f6a38bc19
parentc372ce3c31bf53445e71426b56252ca8238c330f (diff)
ARM: 7809/1: perf: fix event validation for software group leaders
commit c95eb3184ea1a3a2551df57190c81da695e2144b upstream. 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. 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> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
-rw-r--r--arch/arm/kernel/perf_event.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index 778d24857451..0ea8083bc521 100644
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -326,6 +326,9 @@ validate_event(struct pmu_hw_events *hw_events,
struct hw_perf_event fake_event = event->hw;
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;