[PATCH v2 4/4] drm/virtio: release the GEM object on virtio_gpu_vram_create() errors

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

From: Junrui Luo <moonafterrain@outlook.com>

virtio_gpu_vram_create() frees the object with a bare kfree(vram) on
both error paths after drm_gem_private_object_init() has run, and on the
second one after drm_gem_create_mmap_offset() has linked obj->vma_node
into the device's VMA offset manager. The freed object stays in that
interval tree, so a later lookup or insertion walks freed memory, and
the dma_resv and gpuva lock are never destroyed.

Call drm_gem_object_release() before kfree() on both paths.

Fixes: 16845c5d5409 ("drm/virtio: implement blob resources: implement vram object")
Assisted-by: Claude:claude-opus-5
Signed-off-by: Junrui Luo <moonafterrain@outlook.com>
---
 drivers/gpu/drm/virtio/virtgpu_vram.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_vram.c b/drivers/gpu/drm/virtio/virtgpu_vram.c
index 5b4a3ab81cd5..01241ce4d07c 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vram.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vram.c
@@ -215,16 +215,12 @@ int virtio_gpu_vram_create(struct virtio_gpu_device *vgdev,
 
 	/* Create fake offset */
 	ret = drm_gem_create_mmap_offset(obj);
-	if (ret) {
-		kfree(vram);
-		return ret;
-	}
+	if (ret)
+		goto err_release_obj;
 
 	ret = virtio_gpu_resource_id_get(vgdev, &vram->base.hw_res_handle);
-	if (ret) {
-		kfree(vram);
-		return ret;
-	}
+	if (ret)
+		goto err_release_obj;
 
 	virtio_gpu_cmd_resource_create_blob(vgdev, &vram->base, params, NULL,
 					    0);
@@ -240,6 +236,11 @@ int virtio_gpu_vram_create(struct virtio_gpu_device *vgdev,
 
 	*bo_ptr = &vram->base;
 	return 0;
+
+err_release_obj:
+	drm_gem_object_release(obj);
+	kfree(vram);
+	return ret;
 }
 
 void virtio_gpu_vram_map_deferred(struct virtio_gpu_object_vram *vram)

-- 
2.51.2