linux-ext4 - Re: [PATCH] ext4: Fix potential quota deadlock

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]

Message-ID: <20091210162534.GH26516@atrey.karlin.mff.cuni.cz>
Date:	Thu, 10 Dec 2009 17:25:34 +0100
From:	Jan Kara <jack@...e.cz>
To:	Dmitry Monakhov <dmonakhov@...nvz.org>
Cc:	linux-ext4@...r.kernel.org, cmm@...ibm.com
Subject: Re: [PATCH] ext4: Fix potential quota deadlock

> We have to delay vfs_dq_claim_space() until allocation context destruction.
> Currently we have following call-trace:
> ext4_mb_new_blocks()
>   /* task is already holding ac->alloc_semp */
>  ->ext4_mb_mark_diskspace_used
>     ->vfs_dq_claim_space()  /*  acquire dqptr_sem here. Possible deadlock */
>  ->ext4_mb_release_context() /* drop ac->alloc_semp here */
> 
> Let's move quota claiming to ext4_da_update_reserve_space()
> This movement already discussed and approved during discussion
> write() vs chown() race condition.
  The patch looks good to me.

Acked-by: Jan Kara <jack@...e.cz>

									Honza

-- 
Jan Kara <jack@...e.cz>
SuSE CR Labs
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html