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Subject: Re: [PATCH][next][V2] dmaengine: ti: omap-dma: don't allow a null
 od->plat pointer to be dereferenced
To:     Colin King <colin.king@canonical.com>,
        Vinod Koul <vkoul@kernel.org>,
        Dan Williams <dan.j.williams@intel.com>,
        Tony Lindgren <tony@atomide.com>, <dmaengine@vger.kernel.org>
CC:     <kernel-janitors@vger.kernel.org>, <linux-kernel@vger.kernel.org>
References: <20200109131953.157154-1-colin.king@canonical.com>
From:   Peter Ujfalusi <peter.ujfalusi@ti.com>
Message-ID: <7e396a66-41d0-ace8-41b5-1018e6d9d095@ti.com>
Date:   Thu, 9 Jan 2020 17:33:07 +0200
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Colin,

On 09/01/2020 15.19, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> Currently when the call to dev_get_platdata returns null the driver issues
> a warning and then later dereferences the null pointer.  Avoid this issue
> by returning -ENODEV errror rather when the platform data is null and
> change the warning to an appropriate error message.

Thank you for the update!

Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>

> Addresses-Coverity: ("Dereference after null check")
> Fixes: 211010aeb097 ("dmaengine: ti: omap-dma: Pass sdma auxdata to driver and use it")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
> 
> V2: return -ENODEV and change warning to an error message as suggested by
>     Peter Ujfalusi.
> ---
>  drivers/dma/ti/omap-dma.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/dma/ti/omap-dma.c b/drivers/dma/ti/omap-dma.c
> index fc8f7b2fc7b3..a93515015dce 100644
> --- a/drivers/dma/ti/omap-dma.c
> +++ b/drivers/dma/ti/omap-dma.c
> @@ -1658,8 +1658,10 @@ static int omap_dma_probe(struct platform_device *pdev)
>  	if (conf) {
>  		od->cfg = conf;
>  		od->plat = dev_get_platdata(&pdev->dev);
> -		if (!od->plat)
> -			dev_warn(&pdev->dev, "no sdma auxdata needed?\n");
> +		if (!od->plat) {
> +			dev_err(&pdev->dev, "omap_system_dma_plat_info is missing");
> +			return -ENODEV;
> +		}
>  	} else {
>  		od->cfg = &default_cfg;
>  
> 

- Péter

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