ARM: 7356/1: perf: check that we have an event in the PMU IRQ handlers

The PMU IRQ handlers in perf assume that if a counter has overflowed
then perf must be responsible. In the paranoid world of crazy hardware,
this could be false, so check that we do have a valid event before
attempting to dereference NULL in the interrupt path.

Cc: <stable@vger.kernel.org>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/kernel/perf_event_v6.c b/arch/arm/kernel/perf_event_v6.c
index 88bf152..b78af0c 100644 (file)
--- a/arch/arm/kernel/perf_event_v6.c
+++ b/arch/arm/kernel/perf_event_v6.c
@@ -467,23 +467,6 @@ armv6pmu_enable_event(struct hw_perf_event *hwc,
        raw_spin_unlock_irqrestore(&events->pmu_lock, flags);
 }
 
-static int counter_is_active(unsigned long pmcr, int idx)
-{
-       unsigned long mask = 0;
-       if (idx == ARMV6_CYCLE_COUNTER)
-               mask = ARMV6_PMCR_CCOUNT_IEN;
-       else if (idx == ARMV6_COUNTER0)
-               mask = ARMV6_PMCR_COUNT0_IEN;
-       else if (idx == ARMV6_COUNTER1)
-               mask = ARMV6_PMCR_COUNT1_IEN;
-
-       if (mask)
-               return pmcr & mask;
-
-       WARN_ONCE(1, "invalid counter number (%d)\n", idx);
-       return 0;
-}
-
 static irqreturn_t
 armv6pmu_handle_irq(int irq_num,
                    void *dev)
@@ -513,7 +496,8 @@ armv6pmu_handle_irq(int irq_num,
                struct perf_event *event = cpuc->events[idx];
                struct hw_perf_event *hwc;
 
-               if (!counter_is_active(pmcr, idx))
+               /* Ignore if we don't have an event. */
+               if (!event)
                        continue;
 
                /*

diff --git a/arch/arm/kernel/perf_event_v7.c b/arch/arm/kernel/perf_event_v7.c
index 050cc8b..4d7095a 100644 (file)
--- a/arch/arm/kernel/perf_event_v7.c
+++ b/arch/arm/kernel/perf_event_v7.c
@@ -960,6 +960,10 @@ static irqreturn_t armv7pmu_handle_irq(int irq_num, void *dev)
                struct perf_event *event = cpuc->events[idx];
                struct hw_perf_event *hwc;
 
+               /* Ignore if we don't have an event. */
+               if (!event)
+                       continue;
+
                /*
                 * We have a single interrupt for all counters. Check that
                 * each counter has overflowed before we process it.

diff --git a/arch/arm/kernel/perf_event_xscale.c b/arch/arm/kernel/perf_event_xscale.c
index 831e019..a5bbd36 100644 (file)
--- a/arch/arm/kernel/perf_event_xscale.c
+++ b/arch/arm/kernel/perf_event_xscale.c
@@ -255,6 +255,9 @@ xscale1pmu_handle_irq(int irq_num, void *dev)
                struct perf_event *event = cpuc->events[idx];
                struct hw_perf_event *hwc;
 
+               if (!event)
+                       continue;
+
                if (!xscale1_pmnc_counter_has_overflowed(pmnc, idx))
                        continue;
 
@@ -592,6 +595,9 @@ xscale2pmu_handle_irq(int irq_num, void *dev)
                struct perf_event *event = cpuc->events[idx];
                struct hw_perf_event *hwc;
 
+               if (!event)
+                       continue;
+
                if (!xscale2_pmnc_counter_has_overflowed(pmnc, idx))
                        continue;