From: Darren Hart Date: Wed, 5 Aug 2009 19:05:21 +0000 (-0700) Subject: rtmutex: Avoid deadlock in rt_mutex_start_proxy_lock() X-Git-Tag: v4.13~22319^2~2 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=1bbf20835c4e088667a090ce6523a0f70b62dc76;p=mirror_ubuntu-bionic-kernel.git rtmutex: Avoid deadlock in rt_mutex_start_proxy_lock() In the event of a lock steal or owner died, rt_mutex_start_proxy_lock() will give the rt_mutex to the waiting task, but it fails to release the wait_lock. This leads to subsequent deadlocks when other tasks try to acquire the rt_mutex. I also removed a few extra blank lines that really spaced this routine out. I must have been high on the \n when I wrote this originally... Signed-off-by: Darren Hart Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Dinakar Guniguntala Cc: John Stultz LKML-Reference: <4A79D7F1.4000405@us.ibm.com> Signed-off-by: Ingo Molnar --- diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c index fcd107a78c5a..29bd4baf9e75 100644 --- a/kernel/rtmutex.c +++ b/kernel/rtmutex.c @@ -1039,16 +1039,14 @@ int rt_mutex_start_proxy_lock(struct rt_mutex *lock, if (!rt_mutex_owner(lock) || try_to_steal_lock(lock, task)) { /* We got the lock for task. */ debug_rt_mutex_lock(lock); - rt_mutex_set_owner(lock, task, 0); - + spin_unlock(&lock->wait_lock); rt_mutex_deadlock_account_lock(lock, task); return 1; } ret = task_blocks_on_rt_mutex(lock, waiter, task, detect_deadlock); - if (ret && !waiter->task) { /* * Reset the return value. We might have