linux-kernel - Re: 2.6.18.4: flush_workqueue calls 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] [day] [month] [year] [list]

Date:	Wed, 13 Dec 2006 07:41:18 -0500
From:	Trond Myklebust <trond.myklebust@....uio.no>
To:	Arjan van de Ven <arjan@...radead.org>
Cc:	xb <xavier.bru@...l.net>, linux-kernel@...r.kernel.org
Subject: Re: 2.6.18.4: flush_workqueue calls mutex_lock in interrupt
	environment

On Wed, 2006-12-13 at 09:02 +0100, Arjan van de Ven wrote:
> On Wed, 2006-12-13 at 08:25 +0100, xb wrote:
> > Hi all,
> > 
> > Running some IO stress tests on a 8*ways IA64 platform, we got:
> >      BUG: warning at kernel/mutex.c:132/__mutex_lock_common()  message
> > followed by:
> >      Unable to handle kernel paging request at virtual address
> > 0000000000200200
> > oops corresponding to anon_vma_unlink() calling list_del() on a
> > poisonned list.
> > 
> > Having a look to the stack, we see that flush_workqueue() calls
> > mutex_lock() with softirqs disabled.
> 
> something is wrong here... flush_workqueue() is a sleeping function and
> is not allowed to be called in such a context!

It seems utterly insane to have aio_complete() flush a workqueue. That
function has to be called from a number of different environments,
including non-sleep tolerant environments.

For instance it means that directIO on NFS will now cause the rpciod
workqueues to call flush_workqueue(aio_wq), thus slowing down all RPC
activity.

Trond

-
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/