linux-kernel - Re: btrfs: lock inversion between delayed_node->mutex and found->groups

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:	Fri, 04 Apr 2014 17:15:23 -0400
From:	Sasha Levin <sasha.levin@...cle.com>
To:	Jeff Mahoney <jeffm@...e.com>, dsterba@...e.cz, clm@...com,
	jbacik@...com, linux-btrfs@...r.kernel.org,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: btrfs: lock inversion between delayed_node->mutex and found->groups_sem

On 03/26/2014 01:01 PM, Jeff Mahoney wrote:
> On 3/17/14, 9:05 AM, David Sterba wrote:
>>> On Fri, Mar 14, 2014 at 08:12:16PM -0400, Sasha Levin wrote:
>>>>> While fuzzing with trinity inside a KVM tools guest running the latest -next kernel I've stumbled on the following:
>>>>> 
>>>>> [  788.458756]        CPU0                    CPU1 [  788.459188] ----                    ---- [  788.459625] lock(&found->groups_sem); [  788.460041] local_irq_disable(); [  788.460041] lock(&delayed_node->mutex); [  788.460041] lock(&found->groups_sem); [  788.460041]   <Interrupt> [ 788.460041]     lock(&delayed_node->mutex); [  788.460041] [ 788.460041]  *** DEADLOCK *** [  788.460041] [  788.460041] 2 locks held by kswapd3/4199:
>>> 
>>> I've once (3.14-rc5) seen the same warning also caused by xfstests/generic/224
> I think this is from my sysfs patches. We call kobject_add while holding the group_sem. kobject_add ultimately allocates with GFP_KERNEL, so it can enter reclaim. This particular case isn't dangerous, but it could hit while hot-adding a device. The fix should be pretty simple.

Is that fix available anywhere? I'm still seeing the issue in -next.


Thanks,
Sasha
--
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/