diff options
author | Roland Xu <mu001999@outlook.com> | 2024-08-15 10:58:13 +0800 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-09-12 11:11:25 +0200 |
commit | 85f03ca98e07cd0786738b56ae73740bce0ac27f (patch) | |
tree | d50ad460183c8218f6b4a113e71c4d5f9b835ec0 | |
parent | 0b46b4ac929f28ec59de2bea60759d096802bd2a (diff) |
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 <mu001999@outlook.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/ME0P300MB063599BEF0743B8FA339C2CECC802@ME0P300MB0635.AUSP300.PROD.OUTLOOK.COM
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r-- | kernel/locking/rtmutex.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index 21db0df0eb00..bf3a28ee7d8f 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -1624,6 +1624,7 @@ static int __sched rt_mutex_slowlock_block(struct rt_mutex_base *lock, } static void __sched rt_mutex_handle_deadlock(int res, int detect_deadlock, + struct rt_mutex_base *lock, struct rt_mutex_waiter *w) { /* @@ -1636,10 +1637,10 @@ static void __sched rt_mutex_handle_deadlock(int res, int detect_deadlock, if (build_ww_mutex() && w->ww_ctx) return; - /* - * Yell loudly and stop the task right here. - */ + raw_spin_unlock_irq(&lock->wait_lock); + WARN(1, "rtmutex deadlock detected\n"); + while (1) { set_current_state(TASK_INTERRUPTIBLE); schedule(); @@ -1693,7 +1694,7 @@ static int __sched __rt_mutex_slowlock(struct rt_mutex_base *lock, } else { __set_current_state(TASK_RUNNING); remove_waiter(lock, waiter); - rt_mutex_handle_deadlock(ret, chwalk, waiter); + rt_mutex_handle_deadlock(ret, chwalk, lock, waiter); } /* |