drm/amdgpu: amdgpu_ttm_gart_bind set gtt bound flag

Otherwise after the GTT bo is released, the GTT and gart space is freed
but amdgpu_ttm_backend_unbind will not clear the gart page table entry
and leave valid mapping entry pointing to the stale system page. Then
if GPU access the gart address mistakely, it will read undefined value
instead page fault, harder to debug and reproduce the real issue.

Cc: stable@vger.kernel.org
Signed-off-by: Philip Yang <Philip.Yang@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 8722beba494e563fd45c3e2f3cfba05a7f9d38e8..fc418e670fdae27b699bdbefce8051ab128ab76c 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -864,6 +864,7 @@ static void amdgpu_ttm_gart_bind(struct amdgpu_device *adev,
                amdgpu_gart_bind(adev, gtt->offset, ttm->num_pages,
                                 gtt->ttm.dma_address, flags);
        }
+       gtt->bound = true;
 }
 
 /*