diff --git a/arch/x86/events/amd/uncore.c b/arch/x86/events/amd/uncore.c index dbc00b6dd69e..222dfab9225f 100644 --- a/arch/x86/events/amd/uncore.c +++ b/arch/x86/events/amd/uncore.c @@ -265,6 +265,29 @@ static void amd_uncore_del(struct perf_event *event, int flags) hwc->idx = -1; } +static bool amd_uncore_group_valid(struct perf_event *event) +{ + struct amd_uncore_pmu *pmu = event_to_amd_uncore_pmu(event); + struct perf_event *leader = event->group_leader; + struct perf_event *sibling; + int counters = 0; + + if (leader->pmu == event->pmu) + counters++; + + for_each_sibling_event(sibling, leader) { + if (sibling->pmu == event->pmu && + sibling->state > PERF_EVENT_STATE_OFF) + counters++; + } + + /* + * When pmu->event_init() is called, the event is yet to be linked to + * its leader's sibling list, so it is counted separately + */ + return (counters + 1) <= pmu->num_counters; +} + static int amd_uncore_event_init(struct perf_event *event) { struct amd_uncore_pmu *pmu; @@ -282,6 +305,14 @@ static int amd_uncore_event_init(struct perf_event *event) if (!ctx) return -ENODEV; + /* + * Ensure that all events in a group can be scheduled together so that + * a failure can be reported at perf_event_open() time rather than + * silently at pmu->add() time when no free counter is found + */ + if (event->group_leader != event && !amd_uncore_group_valid(event)) + return -EINVAL; + /* * NB and Last level cache counters (MSRs) are shared across all cores * that share the same NB / Last level cache. On family 16h and below,