[PATCH next] drm/amdgpu: Fix double free in amdgpu_userq_fence_driver_alloc()

[Yadav, Arvind]

Please change this also instead of 'goto free_fence_drv' just return err.

         fence_drv = kzalloc(sizeof(*fence_drv), GFP_KERNEL);
         if (!fence_drv) {
                 DRM_ERROR("Failed to allocate memory for fence driver\n");
                 r = -ENOMEM;
                 goto free_fence_drv; // this should be replace by return.
         }

~arvind

On 4/10/2025 9:54 PM, Dan Carpenter wrote:
> The goto frees "fence_drv" so this is a double free bug.  There is no
> need to call amdgpu_seq64_free(adev, fence_drv->va) since the seq64
> allocation failed so change the goto to goto free_fence_drv.  Also
> propagate the error code from amdgpu_seq64_alloc() instead of hard coding
> it to -ENOMEM.
>
> Fixes: e7cf21fbb277 ("drm/amdgpu: Few optimization and fixes for userq fence driver")
> Signed-off-by: Dan Carpenter <dan.carpenter at linaro.org>
> ---
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c | 7 ++-----
>   1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
> index a4953d668972..b012fece91e8 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
> @@ -84,11 +84,8 @@ int amdgpu_userq_fence_driver_alloc(struct amdgpu_device *adev,
>   	/* Acquire seq64 memory */
>   	r = amdgpu_seq64_alloc(adev, &fence_drv->va, &fence_drv->gpu_addr,
>   			       &fence_drv->cpu_addr);
> -	if (r) {
> -		kfree(fence_drv);
> -		r = -ENOMEM;
> -		goto free_seq64;
> -	}
> +	if (r)
> +		goto free_fence_drv;
>   
>   	memset(fence_drv->cpu_addr, 0, sizeof(u64));
>   
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