From: Xiyu Yang Date: Sat, 13 Jun 2020 12:28:38 +0000 (+0800) Subject: drm/ttm: Fix dma_fence refcnt leak in ttm_bo_vm_fault_reserved X-Git-Tag: v5.8-rc3~32^2^2~11 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=37cc4b95d13f311c04aa8e9daacca3905ad45ca7;p=thirdparty%2Fkernel%2Flinux.git drm/ttm: Fix dma_fence refcnt leak in ttm_bo_vm_fault_reserved ttm_bo_vm_fault_reserved() invokes dma_fence_get(), which returns a reference of the specified dma_fence object to "moving" with increased refcnt. When ttm_bo_vm_fault_reserved() returns, local variable "moving" becomes invalid, so the refcount should be decreased to keep refcount balanced. The reference counting issue happens in several exception handling paths of ttm_bo_vm_fault_reserved(). When those error scenarios occur such as "err" equals to -EBUSY, 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 Signed-off-by: Xin Tan Reviewed-by: Christian König Link: https://patchwork.freedesktop.org/patch/370219/ Signed-off-by: Christian König --- diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c index 0ad30b1129821..72100b84c7a90 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c @@ -300,8 +300,10 @@ vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf, break; case -EBUSY: case -ERESTARTSYS: + dma_fence_put(moving); return VM_FAULT_NOPAGE; default: + dma_fence_put(moving); return VM_FAULT_SIGBUS; }