diff options
| -rw-r--r-- | arch/x86/kernel/cpu/perf_event_intel_uncore.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/perf_event_intel_uncore.c b/arch/x86/kernel/cpu/perf_event_intel_uncore.c index 42d00e53175d..9762dbd9f3f7 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_uncore.c +++ b/arch/x86/kernel/cpu/perf_event_intel_uncore.c @@ -42,6 +42,9 @@ struct intel_uncore_box *uncore_pmu_to_box(struct intel_uncore_pmu *pmu, int cpu return box; raw_spin_lock(&uncore_box_lock); + /* Recheck in lock to handle races. */ + if (*per_cpu_ptr(pmu->box, cpu)) + goto out; list_for_each_entry(box, &pmu->box_list, list) { if (box->phys_id == topology_physical_package_id(cpu)) { atomic_inc(&box->refcnt); @@ -49,6 +52,7 @@ struct intel_uncore_box *uncore_pmu_to_box(struct intel_uncore_pmu *pmu, int cpu break; } } +out: raw_spin_unlock(&uncore_box_lock); return *per_cpu_ptr(pmu->box, cpu); |