linux-kernel - Re: [PATCH RT] locking/rtmutex: do lockdep before actual locking in rt_spin

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

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

On Wed, 11 Oct 2017 18:16:46 +0200
Sebastian Andrzej Siewior <bigeasy@...utronix.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@...utronix.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@...dmis.org>

-- Steve