linux-kernel - Re: [patch] inotify: fix deadlock found by lockdep

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] [day] [month] [year] [list]

Date:	Mon, 24 Jul 2006 18:08:37 -0400
From:	Robert Love <rml@...ell.com>
To:	Arjan van de Ven <arjan@...ux.intel.com>
Cc:	Reuben Farrelly <reuben-lkml@...b.net>,
	Ingo Molnar <mingo@...e.hu>,
	John McCutchan <john@...nmccutchan.com>,
	Andrew Morton <akpm@...l.org>,
	Linux Kernel <linux-kernel@...r.kernel.org>, rml@...ian.com,
	viro@...iv.linux.org.uk
Subject: Re: [patch] inotify: fix deadlock found by lockdep

On Mon, 2006-07-24 at 19:21 +0200, Arjan van de Ven wrote:

> inotify_dev_queue_event schedules a kernel_event which does a
> kmem_cache_alloc( , GFP_KERNEL) which may try to shrink slabs, including
> the inode cache .. which then takes iprune_mutex. 
> 
> And voila, there is an AB, a BC, a CD relationship (even a direct BCD),
> and also now a DA relationship -> a circular type AB-BA deadlock but
> involving 4 locks.
> 
> The solution is simple: kernel_event() is NOT allowed to use GFP_KERNEL,
> but must use GFP_NOFS to not cause recursion into the VFS.
> 
> Signed-off-by: Arjan van de Ven <arjan@...ux.intel.com>

Nice catch.

Signed-off-by: Robert Love <rml@...ell.com>

	Robert Love


-
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/