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From: Oleg Nesterov <oleg@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	linux-rt-users <linux-rt-users@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Daniel Bristot de Oliveira <bristot@redhat.com>,
	Clark Williams <williams@redhat.com>,
	Juri Lelli <juri.lelli@redhat.com>,
	jack@suse.com
Subject: Re: [RT WARNING] DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current) with fsfreeze (4.19.25-rt16)
Date: Tue, 30 Apr 2019 16:42:53 +0200	[thread overview]
Message-ID: <20190430144252.GF23020@redhat.com> (raw)
In-Reply-To: <20190430141500.GE23020@redhat.com>

I have cloned linux-rt-devel.git

If I understand correctly, in rt rw_semaphore is actually defined in rwsem_rt.h
so percpu_rwsem_acquire() should probably do

	sem->rw_sem.rtmutex.owner = current;

?


On 04/30, Oleg Nesterov wrote:
>
> Sorry, I don't understand...
> 
> On 04/30, Peter Zijlstra wrote:
> >
> > Thaw then does the reverse, frobs lockdep
> 
> Yes, in particular it does
> 
> 	lockdep_sb_freeze_acquire()
> 		percpu_rwsem_acquire()
> 			sem->rw_sem.owner = current;
> 
> 	
> > and then does: percpu_up_write().
> >
> > percpu_up_write() on up_write(). And note how __up_write() has:
> >
> > 	DEBUG_RWSEMS_WARN_ON(sem->owner != current, sem);
> 
> and everything looks correct, sem->owner == current by the time
> thaw_super_locked() does percpu_up_write/up_write.
> 
> Oleg.


  parent reply	other threads:[~2019-04-30 14:43 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-26  9:34 [RT WARNING] DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current) with fsfreeze (4.19.25-rt16) Juri Lelli
2019-03-28 10:17 ` Sebastian Andrzej Siewior
2019-04-19  8:56 ` Juri Lelli
2019-04-30 12:51   ` Sebastian Andrzej Siewior
2019-04-30 13:28     ` Peter Zijlstra
2019-04-30 13:45       ` Sebastian Andrzej Siewior
2019-04-30 14:01         ` Peter Zijlstra
2019-04-30 14:15       ` Oleg Nesterov
2019-04-30 14:29         ` Peter Zijlstra
2019-04-30 14:42         ` Oleg Nesterov [this message]
2019-04-30 14:44           ` Peter Zijlstra
2019-04-30 14:53             ` Oleg Nesterov
2019-05-01 17:09       ` Peter Zijlstra
2019-05-01 17:26         ` Waiman Long
2019-05-01 18:54           ` Peter Zijlstra
2019-05-01 19:22             ` Davidlohr Bueso
2019-05-01 19:25               ` Peter Zijlstra
2019-05-02 10:09         ` Oleg Nesterov
2019-05-02 11:42           ` Oleg Nesterov
2019-05-03 14:50             ` Peter Zijlstra
2019-05-03 15:25               ` Peter Zijlstra
2019-05-06 16:50               ` Oleg Nesterov
2019-06-19  9:50                 ` Peter Zijlstra
2019-05-03 14:16           ` Peter Zijlstra
2019-05-03 15:37             ` Oleg Nesterov
2019-05-03 15:46               ` Peter Zijlstra

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