On Sat, 9 Sep 2023 17:31:13 +0200 Danilo Krummrich <d...@redhat.com> wrote:
> @@ -807,6 +1262,14 @@ drm_gpuvm_bo_destroy(struct kref *kref) > > drm_gem_gpuva_assert_lock_held(vm_bo->obj); > > + spin_lock(&gpuvm->extobj.lock); > + list_del(&vm_bo->list.entry.extobj); > + spin_unlock(&gpuvm->extobj.lock); > + > + spin_lock(&gpuvm->evict.lock); > + list_del(&vm_bo->list.entry.evict); > + spin_unlock(&gpuvm->evict.lock); > + > list_del(&vm_bo->list.entry.gem); > > drm_gem_object_put(obj); I ran into a UAF situation when the drm_gpuvm_bo object is the last owner of obj, because the lock that's supposed to be held when calling this function (drm_gem_gpuva_assert_lock_held() call above), belongs to obj (either obj->resv, or a driver specific lock that's attached to the driver-specific GEM object). I worked around it by taking a ref to obj before calling lock()+drm_gpuvm_bo_put()+unlock(), and releasing it after I'm node with the lock, but that just feels wrong.
