pebs_status = p->status & cpuc->pebs_enabled;
pebs_status &= (1ULL << x86_pmu.max_pebs_events) - 1;
+ /*
+ * On some CPUs the PEBS status can be zero when PEBS is
+ * racing with clearing of GLOBAL_STATUS.
+ *
+ * Normally we would drop that record, but in the
+ * case when there is only a single active PEBS event
+ * we can assume it's for that event.
+ */
+ if (!pebs_status && cpuc->pebs_enabled &&
+ !(cpuc->pebs_enabled & (cpuc->pebs_enabled-1)))
+ pebs_status = cpuc->pebs_enabled;
+
bit = find_first_bit((unsigned long *)&pebs_status,
x86_pmu.max_pebs_events);
if (bit >= x86_pmu.max_pebs_events)