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authorDarren Hart <dvhltc@us.ibm.com>2009-08-05 15:05:21 -0400
committerIngo Molnar <mingo@elte.hu>2009-08-05 23:50:21 -0400
commit1bbf20835c4e088667a090ce6523a0f70b62dc76 (patch)
tree91fea2bd29abf6be58c55e259d2904de303fcf3e /kernel/rtmutex.c
parent90bc1a658a53f8832ee799685703977a450e5af9 (diff)
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 <dvhltc@us.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Dinakar Guniguntala <dino@in.ibm.com> Cc: John Stultz <johnstul@linux.vnet.ibm.com> LKML-Reference: <4A79D7F1.4000405@us.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/rtmutex.c')
-rw-r--r--kernel/rtmutex.c4
1 files changed, 1 insertions, 3 deletions
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,
1039 if (!rt_mutex_owner(lock) || try_to_steal_lock(lock, task)) { 1039 if (!rt_mutex_owner(lock) || try_to_steal_lock(lock, task)) {
1040 /* We got the lock for task. */ 1040 /* We got the lock for task. */
1041 debug_rt_mutex_lock(lock); 1041 debug_rt_mutex_lock(lock);
1042
1043 rt_mutex_set_owner(lock, task, 0); 1042 rt_mutex_set_owner(lock, task, 0);
1044 1043 spin_unlock(&lock->wait_lock);
1045 rt_mutex_deadlock_account_lock(lock, task); 1044 rt_mutex_deadlock_account_lock(lock, task);
1046 return 1; 1045 return 1;
1047 } 1046 }
1048 1047
1049 ret = task_blocks_on_rt_mutex(lock, waiter, task, detect_deadlock); 1048 ret = task_blocks_on_rt_mutex(lock, waiter, task, detect_deadlock);
1050 1049
1051
1052 if (ret && !waiter->task) { 1050 if (ret && !waiter->task) {
1053 /* 1051 /*
1054 * Reset the return value. We might have 1052 * Reset the return value. We might have