linux-kernel - Re: [PATCH 3/3] drm/msm: Fix 32b size truncation

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Message-ID: <CACu1E7GgGZc7zF5YQxppMj=dG_emNhh1Ld7PbNT_oM_S436xQQ@mail.gmail.com>
Date: Wed, 20 Aug 2025 09:50:54 -0400
From: Connor Abbott <cwabbott0@...il.com>
To: Rob Clark <robin.clark@....qualcomm.com>
Cc: dri-devel@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org, 
	freedreno@...ts.freedesktop.org, Akhil P Oommen <akhilpo@....qualcomm.com>, 
	Dmitry Baryshkov <lumag@...nel.org>, Abhinav Kumar <abhinav.kumar@...ux.dev>, 
	Jessica Zhang <jessica.zhang@....qualcomm.com>, Sean Paul <sean@...rly.run>, 
	Marijn Suijten <marijn.suijten@...ainline.org>, David Airlie <airlied@...il.com>, 
	Simona Vetter <simona@...ll.ch>, open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/3] drm/msm: Fix 32b size truncation

On Tue, Aug 19, 2025 at 7:29 PM Rob Clark <robin.clark@....qualcomm.com> wrote:
>
> Somehow we never noticed this when arm64 became a thing, many years ago.
>
> Signed-off-by: Rob Clark <robin.clark@....qualcomm.com>
> ---
>  drivers/gpu/drm/msm/msm_gem.c | 17 ++++++++---------
>  drivers/gpu/drm/msm/msm_gem.h |  6 +++---
>  2 files changed, 11 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
> index 958bac4e2768..9a935650e5e3 100644
> --- a/drivers/gpu/drm/msm/msm_gem.c
> +++ b/drivers/gpu/drm/msm/msm_gem.c
> @@ -1142,7 +1142,7 @@ static int msm_gem_object_mmap(struct drm_gem_object *obj, struct vm_area_struct
>
>  /* convenience method to construct a GEM buffer object, and userspace handle */
>  int msm_gem_new_handle(struct drm_device *dev, struct drm_file *file,
> -               uint32_t size, uint32_t flags, uint32_t *handle,
> +               size_t size, uint32_t flags, uint32_t *handle,
>                 char *name)
>  {
>         struct drm_gem_object *obj;
> @@ -1208,9 +1208,8 @@ static const struct drm_gem_object_funcs msm_gem_object_funcs = {
>         .vm_ops = &vm_ops,
>  };
>
> -static int msm_gem_new_impl(struct drm_device *dev,
> -               uint32_t size, uint32_t flags,
> -               struct drm_gem_object **obj)
> +static int msm_gem_new_impl(struct drm_device *dev, uint32_t flags,
> +                           struct drm_gem_object **obj)
>  {
>         struct msm_drm_private *priv = dev->dev_private;
>         struct msm_gem_object *msm_obj;
> @@ -1244,7 +1243,7 @@ static int msm_gem_new_impl(struct drm_device *dev,
>         return 0;
>  }
>
> -struct drm_gem_object *msm_gem_new(struct drm_device *dev, uint32_t size, uint32_t flags)
> +struct drm_gem_object *msm_gem_new(struct drm_device *dev, size_t size, uint32_t flags)
>  {
>         struct msm_drm_private *priv = dev->dev_private;
>         struct msm_gem_object *msm_obj;
> @@ -1259,7 +1258,7 @@ struct drm_gem_object *msm_gem_new(struct drm_device *dev, uint32_t size, uint32
>         if (size == 0)
>                 return ERR_PTR(-EINVAL);
>
> -       ret = msm_gem_new_impl(dev, size, flags, &obj);
> +       ret = msm_gem_new_impl(dev, flags, &obj);
>         if (ret)
>                 return ERR_PTR(ret);
>
> @@ -1299,12 +1298,12 @@ struct drm_gem_object *msm_gem_import(struct drm_device *dev,
>         struct msm_drm_private *priv = dev->dev_private;
>         struct msm_gem_object *msm_obj;
>         struct drm_gem_object *obj;
> -       uint32_t size;
> +       size_t size;
>         int ret, npages;

npages should also be size_t.

>
>         size = PAGE_ALIGN(dmabuf->size);
>
> -       ret = msm_gem_new_impl(dev, size, MSM_BO_WC, &obj);
> +       ret = msm_gem_new_impl(dev, MSM_BO_WC, &obj);
>         if (ret)
>                 return ERR_PTR(ret);
>
> @@ -1347,7 +1346,7 @@ struct drm_gem_object *msm_gem_import(struct drm_device *dev,
>         return ERR_PTR(ret);
>  }
>
> -void *msm_gem_kernel_new(struct drm_device *dev, uint32_t size, uint32_t flags,
> +void *msm_gem_kernel_new(struct drm_device *dev, size_t size, uint32_t flags,
>                          struct drm_gpuvm *vm, struct drm_gem_object **bo,
>                          uint64_t *iova)
>  {
> diff --git a/drivers/gpu/drm/msm/msm_gem.h b/drivers/gpu/drm/msm/msm_gem.h
> index 751c3b4965bc..a4cf31853c50 100644
> --- a/drivers/gpu/drm/msm/msm_gem.h
> +++ b/drivers/gpu/drm/msm/msm_gem.h
> @@ -297,10 +297,10 @@ bool msm_gem_active(struct drm_gem_object *obj);
>  int msm_gem_cpu_prep(struct drm_gem_object *obj, uint32_t op, ktime_t *timeout);
>  int msm_gem_cpu_fini(struct drm_gem_object *obj);
>  int msm_gem_new_handle(struct drm_device *dev, struct drm_file *file,
> -               uint32_t size, uint32_t flags, uint32_t *handle, char *name);
> +               size_t size, uint32_t flags, uint32_t *handle, char *name);
>  struct drm_gem_object *msm_gem_new(struct drm_device *dev,
> -               uint32_t size, uint32_t flags);
> -void *msm_gem_kernel_new(struct drm_device *dev, uint32_t size, uint32_t flags,
> +               size_t size, uint32_t flags);
> +void *msm_gem_kernel_new(struct drm_device *dev, size_t size, uint32_t flags,
>                          struct drm_gpuvm *vm, struct drm_gem_object **bo,
>                          uint64_t *iova);
>  void msm_gem_kernel_put(struct drm_gem_object *bo, struct drm_gpuvm *vm);
> --
> 2.50.1
>