On 7/10/26 00:33, Alex Hung wrote:
> Building for ARCH=um with W=1 C=1 makes sparse report "incompatible
> types in comparison expression (different address spaces)" warnings in
> the KFD code, exposed after UML builds were enabled:
>
> - amdgpu_amdkfd_fence.c compares the __rcu-annotated dma_fence.ops
> pointer directly in to_amdgpu_amdkfd_fence().
> - amdgpu_amdkfd_gpuvm.c compares the __rcu eviction fence pointer
> directly in amdgpu_amdkfd_gpuvm_restore_process_bos().
>
> Fixes: af3f2f5db265 ("drm/amdgpu: Remove UML build exclusion from Kconfig")
> Reported-by: kernel test robot <[email protected]>
> Closes:
> https://lore.kernel.org/oe-kbuild-all/[email protected]/
> Cc: Harry Wentland <[email protected]>
> Assisted-by: Copilot:Claude-Opus-4.8
> Signed-off-by: Alex Hung <[email protected]>
Reviewed-by: Christian König <[email protected]>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c | 2 +-
> drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c
> index 6a364357522b..b0299d861903 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c
> @@ -92,7 +92,7 @@ struct amdgpu_amdkfd_fence *to_amdgpu_amdkfd_fence(struct
> dma_fence *f)
> return NULL;
>
> fence = container_of(f, struct amdgpu_amdkfd_fence, base);
> - if (f->ops == &amdkfd_fence_ops)
> + if (rcu_access_pointer(f->ops) == &amdkfd_fence_ops)
> return fence;
>
> return NULL;
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> index 35fe2c974699..f0f516a79424 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> @@ -3096,7 +3096,7 @@ int amdgpu_amdkfd_gpuvm_restore_process_bos(void *info,
> struct dma_fence __rcu *
> process_info->eviction_fence = new_fence;
> replace_eviction_fence(ef, dma_fence_get(&new_fence->base));
> } else {
> - WARN_ONCE(*ef != &process_info->eviction_fence->base,
> + WARN_ONCE(rcu_access_pointer(*ef) !=
> &process_info->eviction_fence->base,
> "KFD eviction fence doesn't match KGD process_info");
> }
>
> --
> 2.43.0
>
