[PATCH] drm/virtio: fix object leak when drm_gem_handle_create() fails

[Junrui Luo via B4 Relay <devnull+moonafterrain.outlook.com@kernel.org>]

From: Junrui Luo <moonafterrain@outlook.com>

virtio_gpu_gem_create() owns the reference taken by
virtio_gpu_object_create(). On the drm_gem_handle_create() error path it
calls drm_gem_object_release() instead of dropping that reference.

drm_gem_object_release() is the inverse of drm_gem_object_init() and does
not touch the reference count or call obj->funcs->free(), so it is only
correct as the last step of a destructor, as in
virtio_gpu_cleanup_object(). Using it here leaves the bo at refcount 1
with no remaining reference, so virtio_gpu_free_object() never runs and
the shmem pages, sg table and virtio_gpu_object are leaked. Since
virtio_gpu_object_create() has already set bo->created,
VIRTIO_GPU_CMD_RESOURCE_UNREF is not queued either, leaking the host-side
resource and the resource id.

drm_gem_handle_create_tail() drops the handle reference on all of its
internal error paths, so the caller only has to drop its own. Use
drm_gem_object_put(), matching the success path below.

Fixes: dc5698e80cf7 ("Add virtio gpu driver.")
Reported-by: Yuhao Jiang <danisjiang@gmail.com>
Assisted-by: Claude:claude-opus-5
Signed-off-by: Junrui Luo <moonafterrain@outlook.com>
---
 drivers/gpu/drm/virtio/virtgpu_gem.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_gem.c b/drivers/gpu/drm/virtio/virtgpu_gem.c
index 66c3f6f74e9c..d2f0b8a3f172 100644
--- a/drivers/gpu/drm/virtio/virtgpu_gem.c
+++ b/drivers/gpu/drm/virtio/virtgpu_gem.c
@@ -45,7 +45,7 @@ static int virtio_gpu_gem_create(struct drm_file *file,
 
 	ret = drm_gem_handle_create(file, &obj->base.base, &handle);
 	if (ret) {
-		drm_gem_object_release(&obj->base.base);
+		drm_gem_object_put(&obj->base.base);
 		return ret;
 	}
 

---
base-commit: f5bbbfec59b4e2fb7520a91de3df8a6174325d6a
change-id: 20260815-virtgpu-gem-create-leak-8620531cd3d8

Best regards,
-- 
Junrui Luo <moonafterrain@outlook.com>