linux-kernel - Re: [PATCH 2/2] loop : Don't hold the lo_ctl_mutex while fput in loop_clr

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]

Date:	Mon, 28 Apr 2008 03:15:31 +0100
From:	Al Viro <viro@...IV.linux.org.uk>
To:	Dave Young <hidave.darkstar@...il.com>
Cc:	linux-kernel@...r.kernel.org, jens.axboe@...cle.com
Subject: Re: [PATCH 2/2] loop : Don't hold the lo_ctl_mutex while fput in
	loop_clr_fd

On Mon, Apr 28, 2008 at 03:13:09AM +0100, Al Viro wrote:
> On Mon, Apr 28, 2008 at 10:10:22AM +0800, Dave Young wrote:
> > [Fixing bug 10504]
> > 
> > If the bakingfile is a block device file, losetuo -d will trigger lockdep
> > warning of "circular locking dependency".
> > 
> > open/release lock order : bdev->bd_mutex ---> lo->lo_ctl_mutex
> > loop_clr_fd lock order  : lo->lo_ctl_mutex ---> bdev->bd_mutex (fput)
> > 
> > Don't hold the lo_ctl_mutex while fput in loop_clr_fd to fix it. It's safe
> > because all loop device state will be consistent here.
> 
> Explain.

BTW, explain also why open() at that spot will not do interesting things
wrt BLKRRPART done a bit below, please.
--
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/