From: Xiyu Yang xiyuyang19@fudan.edu.cn

[ Upstream commit 11425c4519e2c974a100fc984867046d905b9380 ]

ttm_bo_add_move_fence() invokes dma_fence_get(), which returns a reference of the specified dma_fence object to "fence" with increased refcnt.

When ttm_bo_add_move_fence() returns, local variable "fence" becomes invalid, so the refcount should be decreased to keep refcount balanced.

The reference counting issue happens in one exception handling path of ttm_bo_add_move_fence(). When no_wait_gpu flag is equals to true, the function forgets to decrease the refcnt increased by dma_fence_get(), causing a refcnt leak.

Fix this issue by calling dma_fence_put() when no_wait_gpu flag is equals to true.

Signed-off-by: Xiyu Yang xiyuyang19@fudan.edu.cn Signed-off-by: Xin Tan tanxin.ctf@gmail.com Reviewed-by: Christian König christian.koenig@amd.com Link: https://patchwork.freedesktop.org/patch/370221/ Signed-off-by: Christian König christian.koenig@amd.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/ttm/ttm_bo.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index abf165b2f64fc..3ce8ad7603c7f 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -941,8 +941,10 @@ static int ttm_bo_add_move_fence(struct ttm_buffer_object *bo, if (!fence) return 0;

- if (no_wait_gpu) + if (no_wait_gpu) { + dma_fence_put(fence); return -EBUSY; + }

dma_resv_add_shared_fence(bo->base.resv, fence);