linux-kernel - Re: bd_mount_mutex -> bd_mount_sem (was Re: xfs_file_ioctl / xfs_freeze: BUG: warning at kernel/mutex-debug.c:80/debug_mutex

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: <20070108195127.67fe86b8.akpm@osdl.org>
Date:	Mon, 8 Jan 2007 19:51:27 -0800
From:	Andrew Morton <akpm@...l.org>
To:	Eric Sandeen <sandeen@...deen.net>
Cc:	David Chinner <dgc@....com>,
	linux-kernel Mailing List <linux-kernel@...r.kernel.org>,
	xfs@....sgi.com
Subject: Re: bd_mount_mutex -> bd_mount_sem (was Re: xfs_file_ioctl /
 xfs_freeze: BUG: warning at kernel/mutex-debug.c:80/debug_mutex_unlock())

On Mon, 08 Jan 2007 21:38:05 -0600
Eric Sandeen <sandeen@...deen.net> wrote:

> Andrew Morton wrote:
> > On Mon, 08 Jan 2007 21:12:40 -0600
> > Eric Sandeen <sandeen@...deen.net> wrote:
> > 
> >> Andrew Morton wrote:
> >>> On Tue, 9 Jan 2007 10:47:28 +1100
> >>> David Chinner <dgc@....com> wrote:
> >>>
> >>>> On Mon, Jan 08, 2007 at 10:40:54AM -0600, Eric Sandeen wrote:
> >>>>> Sami Farin wrote:
> >>>>>> On Mon, Jan 08, 2007 at 08:37:34 +1100, David Chinner wrote:
> >>>>>> ...
> >>>>>>>> fstab was there just fine after -u.
> >>>>>>> Oh, that still hasn't been fixed?
> >>>>>> Looked like it =)
> >>>>> Hm, it was proposed upstream a while ago:
> >>>>>
> >>>>> http://lkml.org/lkml/2006/9/27/137
> >>>>>
> >>>>> I guess it got lost?
> >>>> Seems like it. Andrew, did this ever get queued for merge?
> >>> Seems not.  I think people were hoping that various nasties in there
> >>> would go away.  We return to userspace with a kernel lock held??
> >> Is a semaphore any worse than the current mutex in this respect?  At 
> >> least unlocking from another thread doesn't violate semaphore rules.  :)
> > 
> > I assume that if we weren't returning to userspace with a lock held, this
> > mutex problem would simply go away.
> > 
> 
> Well nobody's asserting that the filesystem must always be locked & 
> unlocked by the same thread, are they?  That'd be a strange rule to 
> enforce upon the userspace doing the filesystem management wouldn't it? 
>   Or am I thinking about this wrong...

I don't even know what code we're talking about here...

I'm under the impression that XFS will return to userspace with a
filesystem lock held, under the expectation (ie: requirement) that
userspace will later come in and release that lock.

If that's not true, then what _is_ happening in there?

If that _is_ true then, well, that sucks a bit.
-
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/