diff options
| -rw-r--r-- | arch/x86/kernel/cpu/perf_counter.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c index 313638cecbb5..1dcf67057f16 100644 --- a/arch/x86/kernel/cpu/perf_counter.c +++ b/arch/x86/kernel/cpu/perf_counter.c @@ -783,6 +783,10 @@ static int amd_pmu_handle_irq(struct pt_regs *regs, int nmi) counter = cpuc->counters[idx]; hwc = &counter->hw; + + if (counter->hw_event.nmi != nmi) + goto next; + val = x86_perf_counter_update(counter, hwc, idx); if (val & (1ULL << (x86_pmu.counter_bits - 1))) goto next; @@ -869,7 +873,6 @@ perf_counter_nmi_handler(struct notifier_block *self, { struct die_args *args = __args; struct pt_regs *regs; - int ret; if (!atomic_read(&active_counters)) return NOTIFY_DONE; @@ -886,9 +889,16 @@ perf_counter_nmi_handler(struct notifier_block *self, regs = args->regs; apic_write(APIC_LVTPC, APIC_DM_NMI); - ret = x86_pmu.handle_irq(regs, 1); + /* + * Can't rely on the handled return value to say it was our NMI, two + * counters could trigger 'simultaneously' raising two back-to-back NMIs. + * + * If the first NMI handles both, the latter will be empty and daze + * the CPU. + */ + x86_pmu.handle_irq(regs, 1); - return ret ? NOTIFY_STOP : NOTIFY_OK; + return NOTIFY_STOP; } static __read_mostly struct notifier_block perf_counter_nmi_notifier = { |