diff options
| author | John Stultz <jstultz@google.com> | 2024-12-12 14:21:33 -0800 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2024-12-17 17:47:24 +0100 |
| commit | 4a077914578183ec397ad09f7156a357e00e5d72 (patch) | |
| tree | e887d0db4b3e7c82907f5759b85207accde2a2c3 /kernel/locking/rtmutex_api.c | |
| parent | 78d4f34e2115b517bcbfe7ec0d018bbbb6f9b0b8 (diff) | |
locking/rtmutex: Make sure we wake anything on the wake_q when we release the lock->wait_lock
Bert reported seeing occasional boot hangs when running with
PREEPT_RT and bisected it down to commit 894d1b3db41c
("locking/mutex: Remove wakeups from under mutex::wait_lock").
It looks like I missed a few spots where we drop the wait_lock and
potentially call into schedule without waking up the tasks on the
wake_q structure. Since the tasks being woken are ww_mutex tasks
they need to be able to run to release the mutex and unblock the
task that currently is planning to wake them. Thus we can deadlock.
So make sure we wake the wake_q tasks when we unlock the wait_lock.
Closes: https://lore.kernel.org/lkml/20241211182502.2915-1-spasswolf@web.de
Fixes: 894d1b3db41c ("locking/mutex: Remove wakeups from under mutex::wait_lock")
Reported-by: Bert Karwatzki <spasswolf@web.de>
Signed-off-by: John Stultz <jstultz@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20241212222138.2400498-1-jstultz@google.com
Diffstat (limited to 'kernel/locking/rtmutex_api.c')
| -rw-r--r-- | kernel/locking/rtmutex_api.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/locking/rtmutex_api.c b/kernel/locking/rtmutex_api.c index 33ea31d6a7b3..191e4720e546 100644 --- a/kernel/locking/rtmutex_api.c +++ b/kernel/locking/rtmutex_api.c @@ -383,7 +383,7 @@ int __sched rt_mutex_wait_proxy_lock(struct rt_mutex_base *lock, raw_spin_lock_irq(&lock->wait_lock); /* sleep on the mutex */ set_current_state(TASK_INTERRUPTIBLE); - ret = rt_mutex_slowlock_block(lock, NULL, TASK_INTERRUPTIBLE, to, waiter); + ret = rt_mutex_slowlock_block(lock, NULL, TASK_INTERRUPTIBLE, to, waiter, NULL); /* * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might * have to fix that up. |