[PATCH v3] drm/amdgpu: Fix the memory allocation issue in amdgpu_discovery_get_nps_info()

[Alex Deucher]

On Tue, Oct 29, 2024 at 8:53 AM Li Huafei <lihuafei1 at huawei.com> wrote:
>
> Fix two issues with memory allocation in amdgpu_discovery_get_nps_info()
> for mem_ranges:
>
>  - Add a check for allocation failure to avoid dereferencing a null
>    pointer.
>
>  - As suggested by Christophe, use kvcalloc() for memory allocation,
>    which checks for multiplication overflow.
>
> Additionally, assign the output parameters nps_type and range_cnt after
> the kvcalloc() call to prevent modifying the output parameters in case
> of an error return.
>
> Fixes: b194d21b9bcc ("drm/amdgpu: Use NPS ranges from discovery table")
> Suggested-by: Christophe JAILLET <christophe.jaillet at wanadoo.fr>
> Reviewed-by: Lijo Lazar <lijo.lazar at amd.com>
> Signed-off-by: Li Huafei <lihuafei1 at huawei.com>
> ---
> Changes in v3:
>  - As suggested by Christophe, replace kvzalloc() with kvcalloc()
>  - Link to v2: https://lore.kernel.org/lkml/20241029101839.2605713-1-lihuafei1@huawei.com/
>
> Changes in v2:
>  - kvzalloc() call uses 'nps_info->v1.count' instead of '*range_cnt'
>  - Link to v1: https://lore.kernel.org/lkml/20241028215933.2599271-1-lihuafei1@huawei.com/

Applied.  Thanks!

Alex

> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
> index 4bd61c169ca8..620090f092ab 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
> @@ -1757,11 +1757,13 @@ int amdgpu_discovery_get_nps_info(struct amdgpu_device *adev,
>
>         switch (le16_to_cpu(nps_info->v1.header.version_major)) {
>         case 1:
> +               mem_ranges = kvcalloc(nps_info->v1.count,
> +                                     sizeof(struct amdgpu_gmc_memrange),
> +                                     GFP_KERNEL);
> +               if (!mem_ranges)
> +                       return -ENOMEM;
>                 *nps_type = nps_info->v1.nps_type;
>                 *range_cnt = nps_info->v1.count;
> -               mem_ranges = kvzalloc(
> -                       *range_cnt * sizeof(struct amdgpu_gmc_memrange),
> -                       GFP_KERNEL);
>                 for (i = 0; i < *range_cnt; i++) {
>                         mem_ranges[i].base_address =
>                                 nps_info->v1.instance_info[i].base_address;
> --
> 2.25.1
>