* [PATCH RT] locking/rtmutex: do lockdep before actual locking in rt_spin_lock()
@ 2017-10-11 16:16 Sebastian Andrzej Siewior
2017-10-11 16:20 ` Peter Zijlstra
2017-10-11 16:48 ` Steven Rostedt
0 siblings, 2 replies; 3+ messages in thread
From: Sebastian Andrzej Siewior @ 2017-10-11 16:16 UTC (permalink / raw)
To: linux-rt-users; +Cc: linux-kernel, tglx, Peter Zijlstra, Steven Rostedt
rt_spin_lock() should first do the lock annotation via lockdep and then
do the actual locking. That way we learn about the deadlock from lockdep
before it happens.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
kernel/locking/rtmutex.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 79f49d73e4d0..639cfdaae72f 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1153,8 +1153,8 @@ void __sched rt_spin_lock_slowunlock(struct rt_mutex *lock)
void __lockfunc rt_spin_lock(spinlock_t *lock)
{
migrate_disable();
- rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+ rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
}
EXPORT_SYMBOL(rt_spin_lock);
--
2.14.2
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH RT] locking/rtmutex: do lockdep before actual locking in rt_spin_lock()
2017-10-11 16:16 [PATCH RT] locking/rtmutex: do lockdep before actual locking in rt_spin_lock() Sebastian Andrzej Siewior
@ 2017-10-11 16:20 ` Peter Zijlstra
2017-10-11 16:48 ` Steven Rostedt
1 sibling, 0 replies; 3+ messages in thread
From: Peter Zijlstra @ 2017-10-11 16:20 UTC (permalink / raw)
To: Sebastian Andrzej Siewior
Cc: linux-rt-users, linux-kernel, tglx, Steven Rostedt
On Wed, Oct 11, 2017 at 06:16:46PM +0200, Sebastian Andrzej Siewior wrote:
> rt_spin_lock() should first do the lock annotation via lockdep and then
> do the actual locking. That way we learn about the deadlock from lockdep
> before it happens.
Yep, that's the right order.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH RT] locking/rtmutex: do lockdep before actual locking in rt_spin_lock()
2017-10-11 16:16 [PATCH RT] locking/rtmutex: do lockdep before actual locking in rt_spin_lock() Sebastian Andrzej Siewior
2017-10-11 16:20 ` Peter Zijlstra
@ 2017-10-11 16:48 ` Steven Rostedt
1 sibling, 0 replies; 3+ messages in thread
From: Steven Rostedt @ 2017-10-11 16:48 UTC (permalink / raw)
To: Sebastian Andrzej Siewior
Cc: linux-rt-users, linux-kernel, tglx, Peter Zijlstra
On Wed, 11 Oct 2017 18:16:46 +0200
Sebastian Andrzej Siewior <bigeasy@linutronix.de> wrote:
> rt_spin_lock() should first do the lock annotation via lockdep and then
> do the actual locking. That way we learn about the deadlock from lockdep
> before it happens.
>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> ---
> kernel/locking/rtmutex.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
> index 79f49d73e4d0..639cfdaae72f 100644
> --- a/kernel/locking/rtmutex.c
> +++ b/kernel/locking/rtmutex.c
> @@ -1153,8 +1153,8 @@ void __sched rt_spin_lock_slowunlock(struct rt_mutex *lock)
> void __lockfunc rt_spin_lock(spinlock_t *lock)
> {
> migrate_disable();
> - rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
> spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
> + rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
> }
> EXPORT_SYMBOL(rt_spin_lock);
>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
-- Steve
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2017-10-11 16:48 UTC | newest]
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2017-10-11 16:16 [PATCH RT] locking/rtmutex: do lockdep before actual locking in rt_spin_lock() Sebastian Andrzej Siewior
2017-10-11 16:20 ` Peter Zijlstra
2017-10-11 16:48 ` Steven Rostedt
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