Re: [BUG][PATCH]dma-coherent.c: error path bug

From: FUJITA Tomonori
Date: Sun Jun 06 2010 - 22:31:21 EST


On Sun, 6 Jun 2010 13:53:04 +0300
Marin Mitov <mitov@xxxxxxxxxxx> wrote:

> Hi all,
>
> The error path in dma_declare_coherent_memory() leaves
> the pointer dev->dma_mem non completely initialized.
>
> If allocation of dev->dma_mem succeeds,
> but allocation of dev->dma_mem->bitmap fails
> dev->dma_mem is freed, but left non NULL
> and non completely initialized.
>
> Either zero it after being freed (one liner patch), or assign to
> dev->dma_mem only completely initialized structure (patch included).
>
> Comments welcome.
>
> Marin Mitov
>
> Signed-off-by: Marin Mitov <mitov@xxxxxxxxxxx>

Hmm, if dma_declare_coherent_memory() fails, the driver doesn't use
dev->dma_mem. So even if dev->dma_mem points to a freed memory, I'm
not sure that it causes a real problem. We could call this patch a
cleanup though.
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