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  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:	Tue, 18 Dec 2007 15:57:06 +0100
From:	Johannes Berg <johannes@...solutions.net>
To:	Miles Lane <miles.lane@...il.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	netdev <netdev@...r.kernel.org>,
	ipw3945-devel@...ts.sourceforge.net,
	Len Brown <len.brown@...el.com>, Pavel Machek <pavel@...e.cz>,
	"Rafael J. Wysocki" <rjw@...k.pl>
Subject: Re: 2.6.24-rc5-mm1 -- INFO: possible circular locking dependency
	detected -- pm-suspend/5800 is trying to acquire lock


> Sorry.  GMail doesn't support sending unwrapped text, as far as I can
> tell.  I will send the log segment to you as an attachment.  Also,
> when I sent my .config inline to Andrew recently, it tripped his spam
> filter.  I'll attach it as well.

Thanks. This is a bug in iwlwifi.

The problem is actually another case where my workqueue debugging with
lockdep is triggering a warning :))

Here's the thing:

iwl3945_cancel_deferred_work does 

cancel_delayed_work_sync(&priv->init_alive_start);

(which is the "(&(&priv->init_alive_start)->work)" lock)

but it is called from within a locked section of
mutex_lock(&priv->mutex); (locked from iwl3945_pci_suspend)

On the other hand, the task that runs from the init_alive_start
workqueue is iwl3945_bg_init_alive_start() which will lock the same
mutex.

So the deadlock condition is that you can be in
cancel_delayed_work_sync() above while the mutex is locked, and be
waiting for iwl_3945_bg_init_alive_start() which tries to lock the
mutex.

johannes

Download attachment "signature.asc" of type "application/pgp-signature" (829 bytes)

Powered by blists - more mailing lists