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From: Oleg Nesterov <oleg@redhat.com>
To: Dave Chinner <david@fromorbit.com>
Cc: Jan Kara <jack@suse.cz>, Al Viro <viro@zeniv.linux.org.uk>,
	Nikolay Borisov <kernel@kyup.com>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	fstests@vger.kernel.org
Subject: Re: [PATCH V2 2/2] fs/super.c: don't fool lockdep in freeze_super() and thaw_super() paths
Date: Thu, 13 Oct 2016 18:58:08 +0200	[thread overview]
Message-ID: <20161013165807.GA21138@redhat.com> (raw)
In-Reply-To: <20161010010250.GO9806@dastard>

Dave, I am sorry for delay.

On 10/10, Dave Chinner wrote:
>
> So, it's time to waste more time explaining why lockdep is telling
> us about something that *isn't a bug*.
> [... snip ...]

OK, thanks. I am not surprised although I have to admit I wasn't sure.

> Basically, what we are seeing here is yet another case of "lockdep
> is just smart enough to be really dumb" because we cannot fully
> express or cleanly annotate the contexts in which it is being asked
> to validate.

Yes... perhaps we can add the new lockdep helpers to avoid the false-
positives like this one, but so far it is not clear to me what we can do.
Somehow we need to tell it to to avoid check_prev_add() because we know
that the work function won't take sb_internal, but at the same time we
should complain if it actually does this. Lets ignore this patch for now.

Oleg.

  reply	other threads:[~2016-10-13 16:59 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-26 16:07 [PATCH 0/2] (Was: BUG_ON in rcu_sync_func triggered) Oleg Nesterov
2016-09-26 16:07 ` [PATCH 1/2] fs/super.c: fix race between freeze_super() and thaw_super() Oleg Nesterov
2016-09-26 16:11   ` Jan Kara
2016-09-26 16:08 ` [PATCH 2/2] fs/super.c: don't fool lockdep in freeze_super() and thaw_super() paths Oleg Nesterov
2016-09-26 16:18   ` Jan Kara
2016-09-26 16:55     ` [PATCH V2 " Oleg Nesterov
2016-09-27  6:51       ` Jan Kara
2016-09-27  7:14         ` Dave Chinner
2016-09-27 17:29         ` Oleg Nesterov
2016-09-30 17:14           ` Oleg Nesterov
2016-10-02 21:42             ` Dave Chinner
2016-10-03 16:44               ` Oleg Nesterov
2016-10-04 11:43                 ` Oleg Nesterov
2016-10-04 11:48                   ` Michal Hocko
2016-10-06 13:44                     ` Johannes Weiner
2016-10-07 16:52                       ` Oleg Nesterov
2016-10-04 16:58                   ` Oleg Nesterov
2016-10-04 20:03                     ` Dave Chinner
2016-10-05 16:33                       ` Oleg Nesterov
2016-10-04 19:44                   ` Dave Chinner
2016-10-05 16:44                     ` Oleg Nesterov
2016-10-06  7:27                       ` Jan Kara
2016-10-06 17:17                       ` Oleg Nesterov
2016-10-06 21:59                         ` Dave Chinner
2016-10-07 17:15                           ` Oleg Nesterov
2016-10-07 22:52                             ` Dave Chinner
2016-10-09 16:14                               ` Oleg Nesterov
2016-10-10  1:02                                 ` Dave Chinner
2016-10-13 16:58                                   ` Oleg Nesterov [this message]
2016-10-13 17:10 ` [PATCH 0/2] (Was: BUG_ON in rcu_sync_func triggered) Oleg Nesterov

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