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authorWill Deacon <will.deacon@arm.com>2013-08-07 23:39:41 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-08-20 08:26:29 -0700
commit40c366017f537354c64ea8b77d57ca81ecbd6b1d (patch)
tree7e42913df6330e0915064a90dad39964ee86a5cd
parentca4e6a56000ee4b941e2c6d78b5cb32e27245ee0 (diff)
downloadlinux-linaro-stable-40c366017f537354c64ea8b77d57ca81ecbd6b1d.tar.gz
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-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 c82fa0f955cd..ac7306666418 100644
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -324,6 +324,9 @@ 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;