drm/amdgpu: fix potential double drop fence reference

[ Upstream commit 946ab8db6953535a3a88c957db8328beacdfed9d ]

The object fence is not set to NULL after its reference is dropped. As a
result, its reference may be dropped again if error occurs after that,
which may lead to a use after free bug. To avoid the issue, fence is
explicitly set to NULL after dropping its reference.

Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Pan Bian <bianpan2016@163.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Pan Bian 2019-11-06 17:14:45 +08:00 committed by Greg Kroah-Hartman
parent d622edacac
commit e54d9ee1b1

View File

@ -125,6 +125,7 @@ static void amdgpu_do_test_moves(struct amdgpu_device *adev)
}
dma_fence_put(fence);
fence = NULL;
r = amdgpu_bo_kmap(vram_obj, &vram_map);
if (r) {
@ -170,6 +171,7 @@ static void amdgpu_do_test_moves(struct amdgpu_device *adev)
}
dma_fence_put(fence);
fence = NULL;
r = amdgpu_bo_kmap(gtt_obj[i], &gtt_map);
if (r) {