From: Roland Xu Date: Thu, 15 Aug 2024 02:58:13 +0000 (+0800) Subject: rtmutex: Drop rt_mutex::wait_lock before scheduling X-Git-Tag: v5.10.226~4 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=1401da1486dc1cdbef6025fd74a3977df3a3e5d0;p=thirdparty%2Fkernel%2Fstable.git rtmutex: Drop rt_mutex::wait_lock before scheduling commit d33d26036a0274b472299d7dcdaa5fb34329f91b upstream. rt_mutex_handle_deadlock() is called with rt_mutex::wait_lock held. In the good case it returns with the lock held and in the deadlock case it emits a warning and goes into an endless scheduling loop with the lock held, which triggers the 'scheduling in atomic' warning. Unlock rt_mutex::wait_lock in the dead lock case before issuing the warning and dropping into the schedule for ever loop. [ tglx: Moved unlock before the WARN(), removed the pointless comment, massaged changelog, added Fixes tag ] Fixes: 3d5c9340d194 ("rtmutex: Handle deadlock detection smarter") Signed-off-by: Roland Xu Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/ME0P300MB063599BEF0743B8FA339C2CECC802@ME0P300MB0635.AUSP300.PROD.OUTLOOK.COM Signed-off-by: Greg Kroah-Hartman --- diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index f00dd928fc711..c6a2dafd4a3b4 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -1202,6 +1202,7 @@ __rt_mutex_slowlock(struct rt_mutex *lock, int state, } static void rt_mutex_handle_deadlock(int res, int detect_deadlock, + struct rt_mutex *lock, struct rt_mutex_waiter *w) { /* @@ -1211,6 +1212,7 @@ static void rt_mutex_handle_deadlock(int res, int detect_deadlock, if (res != -EDEADLOCK || detect_deadlock) return; + raw_spin_unlock_irq(&lock->wait_lock); /* * Yell lowdly and stop the task right here. */ @@ -1266,7 +1268,7 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state, if (unlikely(ret)) { __set_current_state(TASK_RUNNING); remove_waiter(lock, &waiter); - rt_mutex_handle_deadlock(ret, chwalk, &waiter); + rt_mutex_handle_deadlock(ret, chwalk, lock, &waiter); } /*