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From: Steven Rostedt <rostedt@goodmis.org>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-rt-users@vger.kernel.org, linux-kernel@vger.kernel.org,
	tglx@linutronix.de, Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH RT] locking/rtmutex: do lockdep before actual locking in rt_spin_lock()
Date: Wed, 11 Oct 2017 12:48:51 -0400	[thread overview]
Message-ID: <20171011124851.261415f0@gandalf.local.home> (raw)
In-Reply-To: <20171011161646.baxqesjqm4sip6em@linutronix.de>

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

      parent reply	other threads:[~2017-10-11 16:48 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
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 [this message]

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