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SubjectRe: [PATCH] drm: amdgpu: Use the correct size when allocating memory
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Le 10/08/2020 à 17:42, Dan Carpenter a écrit :
> On Sun, Aug 09, 2020 at 10:34:06PM +0200, Christophe JAILLET wrote:
>> When '*sgt' is allocated, we must allocated 'sizeof(**sgt)' bytes instead
>> of 'sizeof(*sg)'. 'sg' (i.e. struct scatterlist) is smaller than
>> 'sgt' (i.e struct sg_table), so this could lead to memory corruption.
> The sizeof(*sg) is bigger than sizeof(**sgt) so this wastes memory but
> it won't lead to corruption.
>
> 11 struct scatterlist {
> 12 unsigned long page_link;
> 13 unsigned int offset;
> 14 unsigned int length;
> 15 dma_addr_t dma_address;
> 16 #ifdef CONFIG_NEED_SG_DMA_LENGTH
> 17 unsigned int dma_length;
> 18 #endif
> 19 };
>
> 42 struct sg_table {
> 43 struct scatterlist *sgl; /* the list */
> 44 unsigned int nents; /* number of mapped entries */
> 45 unsigned int orig_nents; /* original size of list */
> 46 };
>
> regards,
> dan carpenter


My bad. I read 'struct scatterlist sgl' (without the *)
Thanks for the follow-up, Dan.

Doesn't smatch catch such mismatch?
(I've not run smatch for a while, so it is maybe reported)

Well, the proposal is still valid, even if it has less impact as
initially thought.

Thx for the review.

CJ

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