linux-kernel - Re: [rfc patch] fs,reiserfs: unlock superblock before callling reiserfs_quota_on

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

Message-ID: <1344966273.6724.18.camel@gandalf.stny.rr.com>
Date:	Tue, 14 Aug 2012 13:44:33 -0400
From:	Steven Rostedt <rostedt@...dmis.org>
To:	Mike Galbraith <efault@....de>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	"linux-rt-users@...r.kernel.org" <linux-rt-users@...r.kernel.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [rfc patch] fs,reiserfs: unlock superblock before callling
 reiserfs_quota_on_mount()

On Tue, 2012-08-14 at 19:26 +0200, Mike Galbraith wrote:
> On Tue, 2012-08-14 at 17:18 +0200, Thomas Gleixner wrote: 
> > On Tue, 14 Aug 2012, Mike Galbraith wrote:
> > 
> > > On Tue, 2012-08-14 at 16:39 +0200, Mike Galbraith wrote: 
> > > > On Tue, 2012-08-14 at 10:23 -0400, Steven Rostedt wrote: 
> > > > > On Tue, 2012-08-14 at 15:06 +0200, Mike Galbraith wrote:
> > > > > > Greetings,
> > > > > > 
> > > > > > Using openSUSE's "partitioner" gizmo to set up a reiserfs partition with
> > > > > > quotas and whatnot enabled rewarded me with a deadlock.
> > > > > 
> > > > > Is this just a -rt bug? Can't this deadlock also in mainline?
> > > > 
> > > > It didn't with a NOPREEMPT kernel the one time I tried it, which seemed
> > > > mighty odd when I stared at the rt deadlock.  I'll give it another go, I
> > > > likely just munged q/d NOPREEMPT test.
> > > 
> > > Nope, no screw-up.  Maybe it can deadlock, but it refused to do so.
> > 
> > Lockdep should tell you if it could ...
> 
> I'll give that a shot.  I would expect the thing to gripe.. but then I
> expected the damn thing to deadlock properly with NOPREEMPT too, so.. :)
> 

But would it?

We have kworker blocked on the mutex where the owner did a flush_work(),
and waiting for kworker to finish because of a wait_for_completion(). I
don't see annotation here that will help lockdep catch such a thing.

-- Steve


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/