[PATCH v1 1/1] kfd: fixed memleak about release topology

[Felix Kuehling]

Am 2022-07-15 um 04:07 schrieb ZhiJie.zhang:
> memleak will happend that reload module due to ignore kfree when release topology
>
> Signed-off-by: ZhiJie.zhang <botton_zhang at 163.com>
> ---
>   drivers/gpu/drm/amd/amdkfd/kfd_topology.c | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_topology.c b/drivers/gpu/drm/amd/amdkfd/kfd_topology.c
> index 8d50d207cf66..8b86f56bd50c 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_topology.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_topology.c
> @@ -872,6 +872,7 @@ static void kfd_topology_release_sysfs(void)
>   		}
>   		kobject_del(sys_props.kobj_topology);
>   		kobject_put(sys_props.kobj_topology);
> +		kfree(sys_props.kobj_topology);

Sorry for the late response. This looks incorrect. kobjects are 
reference counted. The underlying memory should be freed by a callback 
when the reference count reaches 0 in kobject_put. Freeing the object 
here explicitly would lead to a double-free.

The callback in this case is kfd_topology_kobj_release, which calls 
kfree. Am I missing anything?

Regards,
   Felix


>   		sys_props.kobj_topology = NULL;
>   	}
>   }