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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>
This commit is contained in:
Will Deacon 2012-03-06 17:34:50 +01:00 committed by Russell King
parent 99c1745b9c
commit f6f5a30c83
3 changed files with 12 additions and 18 deletions
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20
arch/arm/kernel/perf_event_v6.c
View File

@ -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;
/*

4
arch/arm/kernel/perf_event_v7.c
View File

@ -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.

6
arch/arm/kernel/perf_event_xscale.c
View File

@ -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;