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

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

[Junrui Luo via B4 Relay]

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>

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

[Dmitry Osipenko]

On 8/15/26 09:16, Junrui Luo via B4 Relay wrote:
> 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;
>  	}
Could you please fix all other occurrences reported by bot in a v2?

-- 
Best regards,
Dmitry

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

[Junrui Luo]

> On Sep 7, 2026, at 10:07 PM, Dmitry Osipenko <dmitry.osipenko@collabora.com> wrote:
> 
> On 8/15/26 09:16, Junrui Luo via B4 Relay wrote:
>> 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;
>> }
> Could you please fix all other occurrences reported by bot in a v2?

Got it, I’ll work on it.

Thanks,
Junrui

> 
> -- 
> Best regards,
> Dmitry