6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Peter Zijlstra peterz@infradead.org
[ Upstream commit 61988e36dc5457cdff7ae7927e8d9ad1419ee998 ]
While chasing down a missing perf_cgroup_event_disable() elsewhere, Leo Yan found that both perf_put_aux_event() and perf_remove_sibling_event() were also missing one.
Specifically, the rule is that events that switch to OFF,ERROR need to call perf_cgroup_event_disable().
Unify the disable paths to ensure this.
Fixes: ab43762ef010 ("perf: Allow normal events to output AUX data") Fixes: 9f0c4fa111dc ("perf/core: Add a new PERF_EV_CAP_SIBLING event capability") Reported-by: Leo Yan leo.yan@arm.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Link: https://lkml.kernel.org/r/20250605123343.GD35970@noisy.programming.kicks-ass... Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/events/core.c | 51 ++++++++++++++++++++++++++------------------ 1 file changed, 30 insertions(+), 21 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c index 90577a7a3a51e..e9e785542b9f4 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2067,8 +2067,9 @@ perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event) }
static void put_event(struct perf_event *event); -static void event_sched_out(struct perf_event *event, - struct perf_event_context *ctx); +static void __event_disable(struct perf_event *event, + struct perf_event_context *ctx, + enum perf_event_state state);
static void perf_put_aux_event(struct perf_event *event) { @@ -2101,8 +2102,7 @@ static void perf_put_aux_event(struct perf_event *event) * state so that we don't try to schedule it again. Note * that perf_event_enable() will clear the ERROR status. */ - event_sched_out(iter, ctx); - perf_event_set_state(event, PERF_EVENT_STATE_ERROR); + __event_disable(iter, ctx, PERF_EVENT_STATE_ERROR); } }
@@ -2156,18 +2156,6 @@ static inline struct list_head *get_event_list(struct perf_event *event) &event->pmu_ctx->flexible_active; }
-/* - * Events that have PERF_EV_CAP_SIBLING require being part of a group and - * cannot exist on their own, schedule them out and move them into the ERROR - * state. Also see _perf_event_enable(), it will not be able to recover - * this ERROR state. - */ -static inline void perf_remove_sibling_event(struct perf_event *event) -{ - event_sched_out(event, event->ctx); - perf_event_set_state(event, PERF_EVENT_STATE_ERROR); -} - static void perf_group_detach(struct perf_event *event) { struct perf_event *leader = event->group_leader; @@ -2203,8 +2191,15 @@ static void perf_group_detach(struct perf_event *event) */ list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
+ /* + * Events that have PERF_EV_CAP_SIBLING require being part of + * a group and cannot exist on their own, schedule them out + * and move them into the ERROR state. Also see + * _perf_event_enable(), it will not be able to recover this + * ERROR state. + */ if (sibling->event_caps & PERF_EV_CAP_SIBLING) - perf_remove_sibling_event(sibling); + __event_disable(sibling, ctx, PERF_EVENT_STATE_ERROR);
sibling->group_leader = sibling; list_del_init(&sibling->sibling_list); @@ -2437,6 +2432,15 @@ static void perf_remove_from_context(struct perf_event *event, unsigned long fla event_function_call(event, __perf_remove_from_context, (void *)flags); }
+static void __event_disable(struct perf_event *event, + struct perf_event_context *ctx, + enum perf_event_state state) +{ + event_sched_out(event, ctx); + perf_cgroup_event_disable(event, ctx); + perf_event_set_state(event, state); +} + /* * Cross CPU call to disable a performance event */ @@ -2455,13 +2459,18 @@ static void __perf_event_disable(struct perf_event *event,
perf_pmu_disable(event->pmu_ctx->pmu);
+ /* + * When disabling a group leader, the whole group becomes ineligible + * to run, so schedule out the full group. + */ if (event == event->group_leader) group_sched_out(event, ctx); - else - event_sched_out(event, ctx);
- perf_event_set_state(event, PERF_EVENT_STATE_OFF); - perf_cgroup_event_disable(event, ctx); + /* + * But only mark the leader OFF; the siblings will remain + * INACTIVE. + */ + __event_disable(event, ctx, PERF_EVENT_STATE_OFF);
perf_pmu_enable(event->pmu_ctx->pmu); }