[PATCH] drm/amdgpu: : Fix the null pointer dereference for amdgpu_device_switch_gang

[Bob Zhou]

To avoid null pointer dereference reported by Coverity,
so add null pointer check for the return of amdgpu_device_get_gang().

Signed-off-by: Bob Zhou <bob.zhou at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index bcacf2e35eba..c1d82c346daa 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -6569,7 +6569,7 @@ struct dma_fence *amdgpu_device_switch_gang(struct amdgpu_device *adev,
 		if (old == gang)
 			break;
 
-		if (!dma_fence_is_signaled(old))
+		if (!old || !dma_fence_is_signaled(old))
 			return old;
 
 	} while (cmpxchg((struct dma_fence __force **)&adev->gang_submit,
-- 
2.34.1