Re: [PATCH] dmaengine: virt-dma: Fix access after free in vcna_complete()

[Ardelean, Alexandru]

On Fri, 2019-12-20 at 15:11 +0200, Peter Ujfalusi wrote:
> [External]
> 
> vchan_vdesc_fini() is freeing up 'vd' so the access to vd->tx_result is
> via already freed up memory.
> 
> Move the vchan_vdesc_fini() after invoking the callback to avoid this.
> 

Reviewed-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>

> Fixes: 09d5b702b0f97 ("dmaengine: virt-dma: store result on dma
> descriptor")
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
> ---
>  drivers/dma/virt-dma.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/dma/virt-dma.c b/drivers/dma/virt-dma.c
> index ec4adf4260a0..256fc662c500 100644
> --- a/drivers/dma/virt-dma.c
> +++ b/drivers/dma/virt-dma.c
> @@ -104,9 +104,8 @@ static void vchan_complete(unsigned long arg)
>  		dmaengine_desc_get_callback(&vd->tx, &cb);
>  
>  		list_del(&vd->node);
> -		vchan_vdesc_fini(vd);
> -
>  		dmaengine_desc_callback_invoke(&cb, &vd->tx_result);
> +		vchan_vdesc_fini(vd);
>  	}
>  }
>