Re: [ 41/75] ARM: davinci: edma: fix dmaengine induced null pointerdereference on da830

[Luis Henriques]

On Mon, Mar 18, 2013 at 02:07:04PM -0700, Greg Kroah-Hartman wrote:
> 3.8-stable review patch.  If anyone has any objections, please let me know.
> 
> ------------------
> 
> From: Matt Porter <mporter@xxxxxx>
> 
> commit 069552777a121eb39da29de4bc0383483dbe1f7e upstream.
> 
> This adds additional error checking to the private edma api implementation
> to catch the case where the edma_alloc_slot() has an invalid controller
> parameter. The edma dmaengine wrapper driver relies on this condition
> being handled in order to avoid setting up a second edma dmaengine
> instance on DA830.
> 
> Verfied using a DA850 with the second EDMA controller platform instance
> removed to simulate a DA830 which only has a single EDMA controller.
> 
> Reported-by: Tomas Novotny <tomas@xxxxxxxxxx>
> Signed-off-by: Matt Porter <mporter@xxxxxx>
> Tested-by: Tomas Novotny <tomas@xxxxxxxxxx>
> Signed-off-by: Sekhar Nori <nsekhar@xxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> 
> ---
>  arch/arm/mach-davinci/dma.c |    3 +++
>  1 file changed, 3 insertions(+)
> 
> --- a/arch/arm/mach-davinci/dma.c
> +++ b/arch/arm/mach-davinci/dma.c
> @@ -743,6 +743,9 @@ EXPORT_SYMBOL(edma_free_channel);
>   */
>  int edma_alloc_slot(unsigned ctlr, int slot)
>  {
> +	if (!edma_cc[ctlr])
> +		return -EINVAL;
> +
>  	if (slot >= 0)
>  		slot = EDMA_CHAN_SLOT(slot);

I couldn't figure out the reason why this is tagged for v3.7.x+ only.
Shouldn't this be applied to 3.2, 3.4 and 3.5 as well?

Cheers,
--
Luis
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