From ffb684f2aa141eeb0caa6308422e7e05d1ded7c4 Mon Sep 17 00:00:00 2001 From: Luo Gengkun Date: Sun, 20 Sep 2026 07:50:26 +0000 Subject: perf: Fix race between perf_event_exit_task() and perf_pending_task() A race condition exists between perf_event_exit_task() and perf_pending_task() during begin_new_exec(). During begin_new_exec(), perf_event_exit_task() may be called, and the PF_EXITING flag is not set on task. So perf_sigtrap() continues to execute and triggers WARN_ON_ONCE(event->ctx->task != current). Since both task exit and exec paths can call perf_event_exit_task() which sets ctx->task to TASK_TOMBSTONE, fix this by explicitly checking if event->ctx->task equals TASK_TOMBSTONE and dropping the redundant PF_EXITING check. Fixes: 97ba62b27867 ("perf: Add support for SIGTRAP on perf events") Signed-off-by: Luo Gengkun Signed-off-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/20260920075026.990582-1-luogengkun2@huawei.com --- kernel/events/core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index 634d2ccbab82..c2882b5be7c3 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7626,9 +7626,11 @@ static void perf_sigtrap(struct perf_event *event) { /* * Both perf_pending_task() and perf_pending_irq() can race with the - * task exiting. + * task exiting or exec-ing. We can determine if such a race has + * occurred by checking if perf_event_exit_task(), which will set + * ctx->task to TASK_TOMBSTONE, has already been called. */ - if (current->flags & PF_EXITING) + if (event->ctx->task == TASK_TOMBSTONE) return; /* -- cgit v1.2.3