From 1bbf20835c4e088667a090ce6523a0f70b62dc76 Mon Sep 17 00:00:00 2001 From: Darren Hart Date: Wed, 5 Aug 2009 12:05:21 -0700 Subject: [PATCH 1/3] 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 --- kernel/rtmutex.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c index fcd107a78c5..29bd4baf9e7 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 From 9795447f71324d8f14c19ed68b43c883135c3f59 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Fri, 7 Aug 2009 16:37:10 +0800 Subject: [PATCH 2/3] lockdep: Fix file mode of lock_stat /proc/lock_stat is writable. Signed-off-by: Li Zefan Cc: Peter Zijlstra LKML-Reference: <4A7BE7B6.10904@cn.fujitsu.com> Signed-off-by: Ingo Molnar --- kernel/lockdep_proc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c index d7135aa2d2c..e94caa666db 100644 --- a/kernel/lockdep_proc.c +++ b/kernel/lockdep_proc.c @@ -758,7 +758,8 @@ static int __init lockdep_proc_init(void) &proc_lockdep_stats_operations); #ifdef CONFIG_LOCK_STAT - proc_create("lock_stat", S_IRUSR, NULL, &proc_lock_stat_operations); + proc_create("lock_stat", S_IRUSR | S_IWUSR, NULL, + &proc_lock_stat_operations); #endif return 0; From 0e692a94e378628b7d527260ad939894454bcca8 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Fri, 7 Aug 2009 15:10:54 +0800 Subject: [PATCH 3/3] lockdep: Fix typos in documentation s/head/held Signed-off-by: Li Zefan Cc: Peter Zijlstra LKML-Reference: <4A7BD37E.9060806@cn.fujitsu.com> Signed-off-by: Ingo Molnar --- Documentation/lockdep-design.txt | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/Documentation/lockdep-design.txt b/Documentation/lockdep-design.txt index e20d913d591..abf768c681e 100644 --- a/Documentation/lockdep-design.txt +++ b/Documentation/lockdep-design.txt @@ -30,9 +30,9 @@ State The validator tracks lock-class usage history into 4n + 1 separate state bits: - 'ever held in STATE context' -- 'ever head as readlock in STATE context' -- 'ever head with STATE enabled' -- 'ever head as readlock with STATE enabled' +- 'ever held as readlock in STATE context' +- 'ever held with STATE enabled' +- 'ever held as readlock with STATE enabled' Where STATE can be either one of (kernel/lockdep_states.h) - hardirq