[PATCH 2/2] drivers/perf: arm_pmu: Fix NULL pointer dereference during probe

From: Stefan Wahren
Date: Sat Aug 27 2016 - 12:28:11 EST

Patch 7f1d642fbb5c ("drivers/perf: arm-pmu: Fix handling of SPI lacking
interrupt-affinity property") unintended also fixes perf_event support
for bcm2835 which doesn't have PMU interrupts. Unfortunately this change
introduce a NULL pointer dereference on bcm2835, because irq_is_percpu
always expected to be called with a valid IRQ. So fix this regression
by validating the IRQ before.

Signed-off-by: Stefan Wahren <stefan.wahren@xxxxxxxx>
Fixes: 7f1d642fbb5c ("drivers/perf: arm-pmu: Fix handling of SPI lacking \"interrupt-affinity\" property")
drivers/perf/arm_pmu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

Note: checkpatch.pl complains about the fixes tag, but i don't know how to
escape it correctly.

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 1b48bf0..f5e1008 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -970,7 +970,7 @@ static int of_pmu_irq_cfg(struct arm_pmu *pmu)
if (cpumask_weight(&pmu->supported_cpus) == 0) {
int irq = platform_get_irq(pdev, 0);

- if (irq_is_percpu(irq)) {
+ if (irq >= 0 && irq_is_percpu(irq)) {
/* If using PPIs, check the affinity of the partition */
int ret;