[PATCH] drm: cast calculation to __u64 to fix potential integer overflow

[Thierry Reding]

On Tue, Dec 03, 2024 at 10:02:00AM -0600, Gax-c wrote:
> From: Zichen Xie <zichenxie0106 at gmail.com>
> 
> Like commit b0b0d811eac6 ("drm/mediatek: Fix coverity issue with
> unintentional integer overflow"), directly multiply pitch and
> height may lead to integer overflow. Add a cast to avoid it.
> 
> Fixes: 6d1782919dc9 ("drm/cma: Introduce drm_gem_cma_dumb_create_internal()")
> Fixes: dc5698e80cf7 ("Add virtio gpu driver.")
> Fixes: dc6057ecb39e ("drm/tegra: gem: dumb: pitch and size are outputs")
> Signed-off-by: Zichen Xie <zichenxie0106 at gmail.com>
> Cc: stable at vger.kernel.org
> ---
>  drivers/gpu/drm/drm_gem_dma_helper.c | 6 +++---
>  drivers/gpu/drm/tegra/gem.c          | 2 +-
>  drivers/gpu/drm/virtio/virtgpu_gem.c | 2 +-
>  3 files changed, 5 insertions(+), 5 deletions(-)

I don't think this can ever happen. All of these functions should only
ever be called via drm_mode_create_dumb(), which already ensures that
these won't overflow.

Thierry
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