3.2-stable review patch. If anyone has any objections, please let me know.
------------------ From: Will Deacon <[email protected]> commit f6f5a30c834135c9f2fa10400c59ebbdd9188567 upstream. 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. Signed-off-by: Ming Lei <[email protected]> Signed-off-by: Will Deacon <[email protected]> Signed-off-by: Russell King <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/arm/kernel/perf_event_v6.c | 20 ++------------------ arch/arm/kernel/perf_event_v7.c | 4 ++++ arch/arm/kernel/perf_event_xscale.c | 6 ++++++ 3 files changed, 12 insertions(+), 18 deletions(-) --- a/arch/arm/kernel/perf_event_v6.c +++ b/arch/arm/kernel/perf_event_v6.c @@ -463,23 +463,6 @@ armv6pmu_enable_event(struct hw_perf_eve 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) @@ -509,7 +492,8 @@ 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; /* --- a/arch/arm/kernel/perf_event_v7.c +++ b/arch/arm/kernel/perf_event_v7.c @@ -1029,6 +1029,10 @@ static irqreturn_t armv7pmu_handle_irq(i 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. --- a/arch/arm/kernel/perf_event_xscale.c +++ b/arch/arm/kernel/perf_event_xscale.c @@ -253,6 +253,9 @@ xscale1pmu_handle_irq(int irq_num, void struct perf_event *event = cpuc->events[idx]; struct hw_perf_event *hwc; + if (!event) + continue; + if (!xscale1_pmnc_counter_has_overflowed(pmnc, idx)) continue; @@ -590,6 +593,9 @@ xscale2pmu_handle_irq(int irq_num, void struct perf_event *event = cpuc->events[idx]; struct hw_perf_event *hwc; + if (!event) + continue; + if (!xscale2_pmnc_counter_has_overflowed(pmnc, idx)) continue; -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
