Re: [PATCH] drm/radeon/evergreen_cs: fix int overflow errors in cs track offsets

["Christian König" <christian.koenig@amd.com>]

Am 25.07.24 um 20:09 schrieb Nikita Zhandarovich:
> Several cs track offsets (such as 'track->db_s_read_offset')
> either are initialized with or plainly take big enough values that,
> once shifted 8 bits left, may be hit with integer overflow if the
> resulting values end up going over u32 limit.
>
> Some debug prints take this into account (see according dev_warn() in
> evergreen_cs_track_validate_stencil()), even if the actual
> calculated value assigned to local 'offset' variable is missing
> similar proper expansion.
>
> Mitigate the problem by casting the type of right operands to the
> wider type of corresponding left ones in all such cases.
>
> Found by Linux Verification Center (linuxtesting.org) with static
> analysis tool SVACE.
>
> Fixes: 285484e2d55e ("drm/radeon: add support for evergreen/ni tiling informations v11")
> Cc: stable@vger.kernel.org

Well first of all the long cast doesn't makes the value 64bit, it 
depends on the architecture.

Then IIRC the underlying hw can only handle a 32bit address space so 
having the offset as long is incorrect to begin with.

And finally that is absolutely not material for stable.

Regards,
Christian.

> Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru>
> ---
> P.S. While I am not certain that track->cb_color_bo_offset[id]
> actually ends up taking values high enough to cause an overflow,
> nonetheless I thought it prudent to cast it to ulong as well.
>
>   drivers/gpu/drm/radeon/evergreen_cs.c | 18 +++++++++---------
>   1 file changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/radeon/evergreen_cs.c b/drivers/gpu/drm/radeon/evergreen_cs.c
> index 1fe6e0d883c7..d734d221e2da 100644
> --- a/drivers/gpu/drm/radeon/evergreen_cs.c
> +++ b/drivers/gpu/drm/radeon/evergreen_cs.c
> @@ -433,7 +433,7 @@ static int evergreen_cs_track_validate_cb(struct radeon_cs_parser *p, unsigned i
>   		return r;
>   	}
>   
> -	offset = track->cb_color_bo_offset[id] << 8;
> +	offset = (unsigned long)track->cb_color_bo_offset[id] << 8;
>   	if (offset & (surf.base_align - 1)) {
>   		dev_warn(p->dev, "%s:%d cb[%d] bo base %ld not aligned with %ld\n",
>   			 __func__, __LINE__, id, offset, surf.base_align);
> @@ -455,7 +455,7 @@ static int evergreen_cs_track_validate_cb(struct radeon_cs_parser *p, unsigned i
>   				min = surf.nby - 8;
>   			}
>   			bsize = radeon_bo_size(track->cb_color_bo[id]);
> -			tmp = track->cb_color_bo_offset[id] << 8;
> +			tmp = (unsigned long)track->cb_color_bo_offset[id] << 8;
>   			for (nby = surf.nby; nby > min; nby--) {
>   				size = nby * surf.nbx * surf.bpe * surf.nsamples;
>   				if ((tmp + size * mslice) <= bsize) {
> @@ -476,10 +476,10 @@ static int evergreen_cs_track_validate_cb(struct radeon_cs_parser *p, unsigned i
>   			}
>   		}
>   		dev_warn(p->dev, "%s:%d cb[%d] bo too small (layer size %d, "
> -			 "offset %d, max layer %d, bo size %ld, slice %d)\n",
> +			 "offset %ld, max layer %d, bo size %ld, slice %d)\n",
>   			 __func__, __LINE__, id, surf.layer_size,
> -			track->cb_color_bo_offset[id] << 8, mslice,
> -			radeon_bo_size(track->cb_color_bo[id]), slice);
> +			(unsigned long)track->cb_color_bo_offset[id] << 8,
> +			mslice,	radeon_bo_size(track->cb_color_bo[id]), slice);
>   		dev_warn(p->dev, "%s:%d problematic surf: (%d %d) (%d %d %d %d %d %d %d)\n",
>   			 __func__, __LINE__, surf.nbx, surf.nby,
>   			surf.mode, surf.bpe, surf.nsamples,
> @@ -608,7 +608,7 @@ static int evergreen_cs_track_validate_stencil(struct radeon_cs_parser *p)
>   		return r;
>   	}
>   
> -	offset = track->db_s_read_offset << 8;
> +	offset = (unsigned long)track->db_s_read_offset << 8;
>   	if (offset & (surf.base_align - 1)) {
>   		dev_warn(p->dev, "%s:%d stencil read bo base %ld not aligned with %ld\n",
>   			 __func__, __LINE__, offset, surf.base_align);
> @@ -627,7 +627,7 @@ static int evergreen_cs_track_validate_stencil(struct radeon_cs_parser *p)
>   		return -EINVAL;
>   	}
>   
> -	offset = track->db_s_write_offset << 8;
> +	offset = (unsigned long)track->db_s_write_offset << 8;
>   	if (offset & (surf.base_align - 1)) {
>   		dev_warn(p->dev, "%s:%d stencil write bo base %ld not aligned with %ld\n",
>   			 __func__, __LINE__, offset, surf.base_align);
> @@ -706,7 +706,7 @@ static int evergreen_cs_track_validate_depth(struct radeon_cs_parser *p)
>   		return r;
>   	}
>   
> -	offset = track->db_z_read_offset << 8;
> +	offset = (unsigned long)track->db_z_read_offset << 8;
>   	if (offset & (surf.base_align - 1)) {
>   		dev_warn(p->dev, "%s:%d stencil read bo base %ld not aligned with %ld\n",
>   			 __func__, __LINE__, offset, surf.base_align);
> @@ -722,7 +722,7 @@ static int evergreen_cs_track_validate_depth(struct radeon_cs_parser *p)
>   		return -EINVAL;
>   	}
>   
> -	offset = track->db_z_write_offset << 8;
> +	offset = (unsigned long)track->db_z_write_offset << 8;
>   	if (offset & (surf.base_align - 1)) {
>   		dev_warn(p->dev, "%s:%d stencil write bo base %ld not aligned with %ld\n",
>   			 __func__, __LINE__, offset, surf.base_align);