On 6/25/2019 10:58 PM, Jiri Olsa wrote:
On Tue, Jun 25, 2019 at 07:21:35AM -0700, kan.li...@linux.intel.com wrote:From: Kan Liang <kan.li...@linux.intel.com> If a user first sample a PEBS event on a fixed counter, then sample a non-PEBS event on the same fixed counter on Icelake, it will trigger spurious NMI. For example, perf record -e 'cycles:p' -a perf record -e 'cycles' -a The error message for spurious NMI. [June 21 15:38] Uhhuh. NMI received for unknown reason 30 on CPU 2. [ +0.000000] Do you have a strange power saving mode enabled? [ +0.000000] Dazed and confused, but trying to continue The issue was introduced by the following commit: commit 6f55967ad9d9 ("perf/x86/intel: Fix race in intel_pmu_disable_event()") The commit moves the intel_pmu_pebs_disable() after intel_pmu_disable_fixed(), which returns immediately. The related bit of PEBS_ENABLE MSR will never be cleared for the fixed counter. Then a non-PEBS event runs on the fixed counter, but the bit on PEBS_ENABLE is still set, which trigger spurious NMI. Check and disable PEBS for fixed counter after intel_pmu_disable_fixed(). Reported-by: Yi, Ammy <ammy...@intel.com> Signed-off-by: Kan Liang <kan.li...@linux.intel.com> Fixes: 6f55967ad9d9 ("perf/x86/intel: Fix race in intel_pmu_disable_event()") --- arch/x86/events/intel/core.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index 4377bf6a6f82..464316218b77 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -2160,12 +2160,10 @@ static void intel_pmu_disable_event(struct perf_event *event) cpuc->intel_ctrl_host_mask &= ~(1ull << hwc->idx); cpuc->intel_cp_status &= ~(1ull << hwc->idx);- if (unlikely(hwc->config_base == MSR_ARCH_PERFMON_FIXED_CTR_CTRL)) {+ if (unlikely(hwc->config_base == MSR_ARCH_PERFMON_FIXED_CTR_CTRL)) intel_pmu_disable_fixed(hwc); - return; - } - - x86_pmu_disable_event(event); + else + x86_pmu_disable_event(event);oops, I overlooed this, looks good Acked-by: Jiri Olsa <jo...@kernel.org> thanks, jirka
Hi, Could this fix be accepted? Thanks Jin Yao
/* * Needs to be called after x86_pmu_disable_event, -- 2.14.5
