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| author | Yeoreum Yun <yeoreum.yun@arm.com> | 2025-06-02 21:40:49 +0300 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2025-06-05 15:37:52 +0300 |
| commit | 3b7a34aebbdf2a4b7295205bf0c654294283ec82 (patch) | |
| tree | 6fb3b6fa4be3ece8e139f7eb91e3a294001fa87f | |
| parent | 61988e36dc5457cdff7ae7927e8d9ad1419ee998 (diff) | |
| download | linux-3b7a34aebbdf2a4b7295205bf0c654294283ec82.tar.xz | |
perf: Fix dangling cgroup pointer in cpuctx
Commit a3c3c6667("perf/core: Fix child_total_time_enabled accounting
bug at task exit") moves the event->state update to before
list_del_event(). This makes the event->state test in list_del_event()
always false; never calling perf_cgroup_event_disable().
As a result, cpuctx->cgrp won't be cleared properly; causing havoc.
Fixes: a3c3c6667("perf/core: Fix child_total_time_enabled accounting bug at task exit")
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: David Wang <00107082@163.com>
Link: https://lore.kernel.org/all/aD2TspKH%2F7yvfYoO@e129823.arm.com/
| -rw-r--r-- | kernel/events/core.c | 21 |
1 files changed, 6 insertions, 15 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 1cc98b9b3c0b..d78608323916 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2120,18 +2120,6 @@ list_del_event(struct perf_event *event, struct perf_event_context *ctx) if (event->group_leader == event) del_event_from_groups(event, ctx); - /* - * If event was in error state, then keep it - * that way, otherwise bogus counts will be - * returned on read(). The only way to get out - * of error state is by explicit re-enabling - * of the event - */ - if (event->state > PERF_EVENT_STATE_OFF) { - perf_cgroup_event_disable(event, ctx); - perf_event_set_state(event, PERF_EVENT_STATE_OFF); - } - ctx->generation++; event->pmu_ctx->nr_events--; } @@ -2488,11 +2476,14 @@ __perf_remove_from_context(struct perf_event *event, state = PERF_EVENT_STATE_EXIT; if (flags & DETACH_REVOKE) state = PERF_EVENT_STATE_REVOKED; - if (flags & DETACH_DEAD) { - event->pending_disable = 1; + if (flags & DETACH_DEAD) state = PERF_EVENT_STATE_DEAD; - } + event_sched_out(event, ctx); + + if (event->state > PERF_EVENT_STATE_OFF) + perf_cgroup_event_disable(event, ctx); + perf_event_set_state(event, min(event->state, state)); if (flags & DETACH_GROUP) |