From 9cd2f4e304d921459a9348323aff518aee7fdc06 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 18 Sep 2026 17:14:24 -0700 Subject: [PATCH] rtmutex: Use accessor for hrtimer_sleeper ->task field The hrtimer_sleeper structure's ->task field is used as a flag to indicate that the associated hrtimer has expired. This means that the hrtimer handler can be storing to this field while other code is loading from it to check for expiry. Note that additional races appear for hrtimers that can be restarted, which could be argued to be a user error. However, that is no reason to let the compiler introduce additional confusion, and to this end, the hrtimer_sleeper_task_get() was introduced, use of which also has the benefit of avoiding open-code access to hrtimer_sleeper innards. Therefore, apply this accessor to rt_mutex_slowlock_block(). KCSAN located this issue. Signed-off-by: Paul E. McKenney Signed-off-by: Thomas Gleixner Reviewed-by: Dmitry Ilvokhin Link: https://patch.msgid.link/20260919001428.3133388-8-paulmck@kernel.org --- kernel/locking/rtmutex.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index 4728631ae719..5a9534c715b8 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -1644,7 +1644,7 @@ static int __sched rt_mutex_slowlock_block(struct rt_mutex_base *lock, break; } - if (timeout && !timeout->task) { + if (timeout && !hrtimer_sleeper_task_get(timeout)) { ret = -ETIMEDOUT; break; }