linux-kernel - Re: [PATCH] dmaengine: pl330: fix irq race with terminate

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Message-ID: <20180725123010.GR3661@vkoul-mobl>
Date:   Wed, 25 Jul 2018 18:00:10 +0530
From:   Vinod <vkoul@...nel.org>
To:     John Keeping <john@...anate.com>
Cc:     dmaengine@...r.kernel.org, Dan Williams <dan.j.williams@...el.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] dmaengine: pl330: fix irq race with terminate_all

On 17-07-18, 11:48, John Keeping wrote:
> In pl330_update() when checking if a channel has been aborted, the
> channel's lock is not taken, only the overall pl330_dmac lock.  But in
> pl330_terminate_all() the aborted flag (req_running==-1) is set under
> the channel lock and not the pl330_dmac lock.
> 
> With threaded interrupts, this leads to a potential race:
> 
>     pl330_terminate_all	        pl330_update
>     -------------------         ------------
>     lock channel
>                                 entry
>     lock pl330
>     _stop channel
>     unlock pl330
>                                 lock pl330
>                                 check req_running != -1
>     req_running = -1
>                                 _start channel
> 

Applied, thanks

-- 
~Vinod