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Re: [PATCH RT] locking/rtmutex: don't drop the wait_lock twice

From Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Newsgroups linux.kernel
Subject Re: [PATCH RT] locking/rtmutex: don't drop the wait_lock twice
Date 2017-09-21 18:50 +0200
Message-ID <uscPM-3sF-9@gated-at.bofh.it> (permalink)
References <usbTI-2TP-19@gated-at.bofh.it> <uscG5-3pb-1@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On 2017-09-21 12:31:05 [-0400], Steven Rostedt wrote:
> > diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
> > index f03876322d4a..79f49d73e4d0 100644
> > --- a/kernel/locking/rtmutex.c
> > +++ b/kernel/locking/rtmutex.c
> > @@ -2281,7 +2281,6 @@ int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
> >  	raw_spin_lock(&task->pi_lock);
> >  	if (task->pi_blocked_on) {
> >  		raw_spin_unlock(&task->pi_lock);
> > -		raw_spin_unlock_irq(&lock->wait_lock);
> 
> Hmm, before this patch, irqs are enabled when returning with -EAGAIN.
> But now they are not. Should that be:
> 
> 		raw_spin_unlock_irq(&taks->pi_lock);
> 
> or is there something that changes this?

There is something else. Before that futex rework there was just
rt_mutex_start_proxy_lock() and it did lock & unlock of ->wait_lock.
This no longer the case after the rework. So now the caller does this.

> -- Steve

Sebastian

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Thread

[PATCH RT] locking/rtmutex: don't drop the wait_lock twice Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2017-09-21 17:50 +0200
  Re: [PATCH RT] locking/rtmutex: don't drop the wait_lock twice Steven Rostedt <rostedt@goodmis.org> - 2017-09-21 18:40 +0200
    Re: [PATCH RT] locking/rtmutex: don't drop the wait_lock twice Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2017-09-21 18:50 +0200
      Re: [PATCH RT] locking/rtmutex: don't drop the wait_lock twice Steven Rostedt <rostedt@goodmis.org> - 2017-09-21 19:00 +0200
        Re: [PATCH RT] locking/rtmutex: don't drop the wait_lock twice Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2017-09-21 19:40 +0200
          Re: [PATCH RT] locking/rtmutex: don't drop the wait_lock twice Steven Rostedt <rostedt@goodmis.org> - 2017-09-21 20:00 +0200
            Re: [PATCH RT] locking/rtmutex: don't drop the wait_lock twice Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2017-09-21 20:20 +0200
              [PATCH RT v2] locking/rtmutex: don't drop the wait_lock twice Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2017-09-21 20:50 +0200

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