Re: [PATCH] drm: amdgpu: Use the correct size when allocating memory

[Alex Deucher <alexdeucher@gmail.com>]

Applied and updated the commit message to reflect the sizes.

Thanks!

Alex

On Mon, Aug 10, 2020 at 3:07 PM Marion & Christophe JAILLET
<christophe.jaillet@wanadoo.fr> wrote:
>
>
> 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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