Re: [PATCH] Staging: drivers/gpu/drm/amd/amdgpu: Fix null pointer deference in amdkfd_fence_get_timeline_name

[Christian König]

Am 20.09.24 um 11:09 schrieb Dipendra Khadka:
'''
drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c:108:9: error: Null pointer 
dereference: fence [nullPointer]
  return fence->timeline_name;
         ^
'''
The method to_amdgpu_amdkfd_fence can return NULL incase of empty f
or f->ops != &amdkfd_fence_ops.Hence, check has been added .
If fence is null , then null is returned.

Well NAK, completely nonsense. Calling the function with a NULL fence is 
illegal.

Regards,
Christian.


Signed-off-by: Dipendra Khadka <kdipendr...@gmail.com>
---
  drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c | 3 +++
  1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c
index 1ef758ac5076..2313babcc944 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_fence.c
@@ -105,6 +105,9 @@ static const char *amdkfd_fence_get_timeline_name(struct 
dma_fence *f)
  {
        struct amdgpu_amdkfd_fence *fence = to_amdgpu_amdkfd_fence(f);
  
+	if (!fence)
+               return NULL;
+
        return fence->timeline_name;
  }