6.12-stable review patch. If anyone has any objections, please let me know.
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From: Peter Zijlstra peterz@infradead.org
[ Upstream commit 8feb053d53194382fcfb68231296fdc220497ea6 ]
Gabriele noted that in case of signal_pending_state(), the tracepoint sees a stale task-state.
Fixes: fa2c3254d7cf ("sched/tracing: Don't re-read p->state when emitting sched_switch event") Reported-by: Gabriele Monaco gmonaco@redhat.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Cc: Valentin Schneider vschneid@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/sched/core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index e9bb1b4c58421..814abc7ad994a 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6517,12 +6517,14 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) * Otherwise marks the task's __state as RUNNING */ static bool try_to_block_task(struct rq *rq, struct task_struct *p, - unsigned long task_state) + unsigned long *task_state_p) { + unsigned long task_state = *task_state_p; int flags = DEQUEUE_NOCLOCK;
if (signal_pending_state(task_state, p)) { WRITE_ONCE(p->__state, TASK_RUNNING); + *task_state_p = TASK_RUNNING; return false; }
@@ -6656,7 +6658,7 @@ static void __sched notrace __schedule(int sched_mode) goto picked; } } else if (!preempt && prev_state) { - try_to_block_task(rq, prev, prev_state); + try_to_block_task(rq, prev, &prev_state); switch_count = &prev->nvcsw; }