Re: [PATCH v1] migration: tls: fix memory leak in migration_tls_get_creds

["Daniel P. Berrangé" <berrange@redhat.com>]

On Wed, Jul 22, 2020 at 11:32:28AM +0800, Zhenyu Ye wrote:
> Currently migration_tls_get_creds() adds the reference of creds
> but there was no place to unref it.  So the OBJECT(creds) will
> never be freed and result in memory leak.
> 
> The leak stack:
> Direct leak of 104 byte(s) in 1 object(s) allocated from:
>     #0 0xffffa88bd20b in __interceptor_malloc (/usr/lib64/libasan.so.4+0xd320b)
>     #1 0xffffa7f0cb1b in g_malloc (/usr/lib64/libglib-2.0.so.0+0x58b1b)
>     #2 0x14b58cb in object_new_with_type qom/object.c:634
>     #3 0x14b597b in object_new qom/object.c:645
>     #4 0x14c0e4f in user_creatable_add_type qom/object_interfaces.c:59
>     #5 0x141c78b in qmp_object_add qom/qom-qmp-cmds.c:312
>     #6 0x140e513 in qmp_marshal_object_add qapi/qapi-commands-qom.c:279
>     #7 0x176ba97 in do_qmp_dispatch qapi/qmp-dispatch.c:165
>     #8 0x176bee7 in qmp_dispatch qapi/qmp-dispatch.c:208
>     #9 0x136e337 in monitor_qmp_dispatch monitor/qmp.c:150
>     #10 0x136eae3 in monitor_qmp_bh_dispatcher monitor/qmp.c:239
>     #11 0x1852e93 in aio_bh_call util/async.c:89
>     #12 0x18531b7 in aio_bh_poll util/async.c:117
>     #13 0x18616bf in aio_dispatch util/aio-posix.c:459
>     #14 0x1853f37 in aio_ctx_dispatch util/async.c:268
>     #15 0xffffa7f06a7b in g_main_context_dispatch (/usr/lib64/libglib-2.0.so.0+0x52a7b)
> 
> Since we're fine to use the borrowed reference when using the creds,
> so just remove the object_ref() in migration_tls_get_creds().
> 
> Signed-off-by: Zhenyu Ye <yezhenyu2@huawei.com>
> ---
>  migration/tls.c | 1 -
>  1 file changed, 1 deletion(-)

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>


> 
> diff --git a/migration/tls.c b/migration/tls.c
> index 5171afc6c4..7a02ec8656 100644
> --- a/migration/tls.c
> +++ b/migration/tls.c
> @@ -58,7 +58,6 @@ migration_tls_get_creds(MigrationState *s,
>          return NULL;
>      }
>  
> -    object_ref(OBJECT(ret));
>      return ret;
>  }
>  
> -- 
> 2.19.1
> 
> 

Regards,
Daniel
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