Commit 2c528fa3 authored Nov 06, 2019 by Pan Bian Committed by Greg Kroah-Hartman Dec 31, 2019

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>

parent 7b3fe663

drivers/gpu/drm/amd/amdgpu/amdgpu_test.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -138,6 +138,7 @@ 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) {
		@@ -183,6 +184,7 @@ 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) {