linux-kernel - blk_throtl_exit taking q->queue

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-next>] [day] [month] [year] [list]

Date:	Wed, 16 Feb 2011 18:31:14 +1100
From:	NeilBrown <neilb@...e.de>
To:	Vivek Goyal <vgoyal@...hat.com>
Cc:	Jens Axboe <jaxboe@...ionio.com>, linux-kernel@...r.kernel.org
Subject: blk_throtl_exit  taking q->queue_lock is problematic

Hi,

 I recently discovered that blk_throtl_exit takes ->queue_lock when a blockdev
is finally released.

This is a problem for because by that time the queue_lock doesn't exist any
more.  It is in a separate data structure controlled by the RAID personality
and by the time that the block device is being destroyed the raid personality
has shutdown and the data structure containing the lock has been freed.

This has not been a problem before.  Nothing else takes queue_lock after
blk_cleanup_queue.

I could of course set queue_lock to point to __queue_lock and initialise that,
but it seems untidy and probably violates some locking requirements.

Is there some way you could use some other lock - maybe a global lock, or
maybe used __queue_lock directly ???

Thanks,
NeilBrown
--
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/