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SubjectRe: [PATCH] drivers/base: wrong return value of dmam_declare_coherent_memory
Vyacheslav,

thanks for your patch.

For now it introduces a new bug.

Vyacheslav Yurkov <uvv.mail <at> gmail.com> writes:

>
> Hi guys,
> I found an issue in managed version of dma_declare_coherent_memory,
> i.e. in dmam_declare_coherent_memory. It looks like the return value
> of dma_declare_coherent_memory is zero in case of error and a
> requested flag on success,

You should take this into account and not ignore the value of rc at all
by using flags instead, which is not being altered by
dma_declare_coherent_memory() making the latter appear to succeed
always.

> which dmam_* version doesn't take into
> account and this leads to leaking of resources.
>
> ---
> Yours sincerely,
> Vyacheslav V. Yurkov
>
> P.S.: I'm not subscribed to the maillist, so please include me in CC
> when responding to this Email.
>
> ---
> --- linux-4.5.2/drivers/base/dma-mapping.c.orig 2016-04-20
> 08:46:35.000000000 +0200
> +++ linux-4.5.2/drivers/base/dma-mapping.c 2016-04-28 10:15:34.295080491
> +0200
> <at> <at> -198,10 +198,15 <at> <at> int dmam_declare_coherent_memory(struct
>
> rc = dma_declare_coherent_memory(dev, phys_addr, device_addr, size,
> flags);
> - if (rc == 0)
> +
> + if ((flags & DMA_MEMORY_MAP) == DMA_MEMORY_MAP ||
> + (flags & DMA_MEMORY_IO) == DMA_MEMORY_IO) {
> devres_add(dev, res);
> - else
> + rc = 0;
> + } else {
> devres_free(res);
> + rc = -ENOMEM;
> + }
>
> return rc;
> }
>
> Signed-off-by: Vyacheslav Yurkov <uvv.mail <at> gmail.com>
>

Best Regards,
Andrey

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