From: Vinod Koul <vkoul@kernel.org>
To: Sebastian von Ohr <vonohr@smaract.com>,
Appana Durga Kedareswara rao <appana.durga.rao@xilinx.com>,
Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>,
Michal Simek <michal.simek@xilinx.com>
Cc: dmaengine@vger.kernel.org
Subject: Re: [PATCH] dmaengine: xilinx_dma: Add missing check for empty list
Date: Fri, 6 Mar 2020 19:04:27 +0530 [thread overview]
Message-ID: <20200306133427.GG4148@vkoul-mobl> (raw)
In-Reply-To: <20200303130518.333-1-vonohr@smaract.com>
On 03-03-20, 14:05, Sebastian von Ohr wrote:
> The DMA transfer might finish just after checking the state with
> dma_cookie_status, but before the lock is acquired. Not checking
> for an empty list in xilinx_dma_tx_status may result in reading
> random data or data corruption when desc is written to. This can
> be reliably triggered by using dma_sync_wait to wait for DMA
> completion.
Appana, Radhey can you please test this..?
>
> Signed-off-by: Sebastian von Ohr <vonohr@smaract.com>
> ---
> drivers/dma/xilinx/xilinx_dma.c | 20 ++++++++++----------
> 1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c
> index a9c5d5cc9f2b..5d5f1d0ce16c 100644
> --- a/drivers/dma/xilinx/xilinx_dma.c
> +++ b/drivers/dma/xilinx/xilinx_dma.c
> @@ -1229,16 +1229,16 @@ static enum dma_status xilinx_dma_tx_status(struct dma_chan *dchan,
> return ret;
>
> spin_lock_irqsave(&chan->lock, flags);
> -
> - desc = list_last_entry(&chan->active_list,
> - struct xilinx_dma_tx_descriptor, node);
> - /*
> - * VDMA and simple mode do not support residue reporting, so the
> - * residue field will always be 0.
> - */
> - if (chan->has_sg && chan->xdev->dma_config->dmatype != XDMA_TYPE_VDMA)
> - residue = xilinx_dma_get_residue(chan, desc);
> -
> + if (!list_empty(&chan->active_list)) {
> + desc = list_last_entry(&chan->active_list,
> + struct xilinx_dma_tx_descriptor, node);
> + /*
> + * VDMA and simple mode do not support residue reporting, so the
> + * residue field will always be 0.
> + */
> + if (chan->has_sg && chan->xdev->dma_config->dmatype != XDMA_TYPE_VDMA)
> + residue = xilinx_dma_get_residue(chan, desc);
> + }
> spin_unlock_irqrestore(&chan->lock, flags);
>
> dma_set_residue(txstate, residue);
> --
> 2.17.1
--
~Vinod
next prev parent reply other threads:[~2020-03-06 13:34 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-03 13:05 [PATCH] dmaengine: xilinx_dma: Add missing check for empty list Sebastian von Ohr
2020-03-06 13:34 ` Vinod Koul [this message]
2020-03-06 13:57 ` Radhey Shyam Pandey
2020-03-11 9:16 ` Vinod Koul
2020-04-07 7:52 ` Sebastian von Ohr
2020-04-07 16:03 ` Radhey Shyam Pandey
2020-04-08 7:12 ` Sebastian von Ohr
2020-04-08 14:06 ` Radhey Shyam Pandey
2020-04-08 15:19 ` Sebastian von Ohr
2020-04-09 7:40 ` Radhey Shyam Pandey
2020-04-15 16:12 ` Vinod Koul
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