linux-kernel - Re: Possible deadlock in jfs

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:	Sat, 23 May 2009 20:26:50 -0500
From:	Dave Kleikamp <shaggy@...ux.vnet.ibm.com>
To:	Jan Kucera <kucera.jan.cz@...il.com>
Cc:	JFS Discussion <jfs-discussion@...ts.sourceforge.net>,
	linux-kernel@...r.kernel.org
Subject: Re: Possible deadlock in jfs_imap.c?

On Sat, 2009-05-23 at 17:19 +0200, Jan Kucera wrote:
> Hi,
> 
> for my master thesis, I've designed static checker for finding deadlocks in C.
> My tool found some possible deadlock in file fs/jfs/jfs_imap.c
> between JFS_IP(ipimap)->commit_mutex and  imap->im_aglock[agno].
> 
> Reason of this problem is probably missed unlocking of
> JFS_IP(ipimap)->commit_mutex in branch starting at line 2564 which
> leaves JFS_IP(ipimap)->commit_mutex locked:
> 
>     in function diNewIAG(..)
>         locking mutex_lock(&JFS_IP(ipimap)->commit_mutex) at line 2540
>         condition at line 2543 is false
>         condition at line 2564 is true
>         goto out: at 2579
>         IAGFREE_UNLOCK(imap); at line 2654
>     return from diNewIAG(..) at line 2656
> 
> Version of kernel is 2.6.28 (maybe this code is in newer versions too).
> Could someone confirm, that this is a real bug? Thank you for your time.

Yes, it looks like a real bug.  As the comment states, it's an unlikely
error path. This would explain how it went undetected this long.  Should
be fixed anyway.

Thanks,
Shaggy
-- 
David Kleikamp
IBM Linux Technology Center

--
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/