linux-kernel - Re: [PATCH v2] dmaengine: edma: Implement device

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

Message-ID: <56BC5759.80000@metafoo.de>
Date:	Thu, 11 Feb 2016 10:41:45 +0100
From:	Lars-Peter Clausen <lars@...afoo.de>
To:	Peter Ujfalusi <peter.ujfalusi@...com>, vinod.koul@...el.com
Cc:	linux-kernel@...r.kernel.org, dmaengine@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, nsekhar@...com,
	linux-omap@...r.kernel.org
Subject: Re: [PATCH v2] dmaengine: edma: Implement device_synchronize callback

On 02/11/2016 10:08 AM, Peter Ujfalusi wrote:
> We need the callback to support the dmaengine_terminate_sync().
> 
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@...com>

Looks good, but I noticed a slight race condition in
edma_completion_handler(). You need to fetch echan->desc while holding the
vchan.lock. Otherwise this can race against terminate_all() and the callback
might get scheduled even though terminate_all() completed and then there is
a race where the synchronize() operation could be called before the callback
gets scheduled, which means it doesn't do its intended job. Highly unlikely
to happen, but theoretically possible.