On Thu, Sep 26, 2013 at 09:51:23AM +0200, Takashi Iwai wrote:

Hi,

sorry for the lat response, as I've been traveling in the last weeks.

At Thu, 19 Sep 2013 22:53:02 +0100, Russell King wrote:

...

This code sequence is unsafe in modules:

static u64 mask = DMA_BIT_MASK(something); ... if (!dev->dma_mask) dev->dma_mask = &mask;

as if a module is reloaded, the mask will be pointing at the original module's mask address, and this can lead to oopses. Moreover, they all follow this with:

if (!dev->coherent_dma_mask) dev->coherent_dma_mask = mask;

where 'mask' is the same value as the statically defined mask, and this bypasses the architecture's check on whether the DMA mask is possible.

Fix these issues by using the new dma_coerce_coherent_and_mask() function.

Signed-off-by: Russell King rmk+kernel@arm.linux.org.uk

Applied with Mark's ack now.

Which is a very stupid thing to do because you won't have dma_coerce_coherent_and_mask() in your tree, so all these drivers will fail to build for you.