6.15-stable review patch. If anyone has any objections, please let me know.
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From: Luo Gengkun luogengkun@huaweicloud.com
[ Upstream commit 7b4c5a37544ba22c6ebe72c0d4ea56c953459fa5 ]
commit 3172fb986666 ("perf/core: Fix WARN in perf_cgroup_switch()") try to fix a concurrency problem between perf_cgroup_switch and perf_cgroup_event_disable. But it does not to move the WARN_ON_ONCE into lock-protected region, so the warning is still be triggered.
Fixes: 3172fb986666 ("perf/core: Fix WARN in perf_cgroup_switch()") Signed-off-by: Luo Gengkun luogengkun@huaweicloud.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Link: https://lkml.kernel.org/r/20250626135403.2454105-1-luogengkun@huaweicloud.co... Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/events/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c index 2d1131e2cfc02..53d2457f5c08a 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -951,8 +951,6 @@ static void perf_cgroup_switch(struct task_struct *task) if (READ_ONCE(cpuctx->cgrp) == NULL) return;
- WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0); - cgrp = perf_cgroup_from_task(task, NULL); if (READ_ONCE(cpuctx->cgrp) == cgrp) return; @@ -964,6 +962,8 @@ static void perf_cgroup_switch(struct task_struct *task) if (READ_ONCE(cpuctx->cgrp) == NULL) return;
+ WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0); + perf_ctx_disable(&cpuctx->ctx, true);
ctx_sched_out(&cpuctx->ctx, NULL, EVENT_ALL|EVENT_CGROUP);