Re: [PATCH] qom-hmp-cmds: fix a memleak in hmp_qom_get

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

Hi Pan,

On 6/3/20 9:03 AM, Pan Nengyuan wrote:
> 'obj' forgot to free at the end of hmp_qom_get(). Fix that.
> 
> The leak stack:
> Direct leak of 40 byte(s) in 1 object(s) allocated from:
>     #0 0x7f4e3a779ae8 in __interceptor_malloc (/lib64/libasan.so.5+0xefae8)
>     #1 0x7f4e398f91d5 in g_malloc (/lib64/libglib-2.0.so.0+0x531d5)
>     #2 0x55c9fd9a3999 in qstring_from_substr /build/qemu/src/qobject/qstring.c:45
>     #3 0x55c9fd894bd3 in qobject_output_type_str /build/qemu/src/qapi/qobject-output-visitor.c:175
>     #4 0x55c9fd894bd3 in qobject_output_type_str /build/qemu/src/qapi/qobject-output-visitor.c:168
>     #5 0x55c9fd88b34d in visit_type_str /build/qemu/src/qapi/qapi-visit-core.c:308
>     #6 0x55c9fd59aa6b in property_get_str /build/qemu/src/qom/object.c:2064
>     #7 0x55c9fd5adb8a in object_property_get_qobject /build/qemu/src/qom/qom-qobject.c:38
>     #8 0x55c9fd4a029d in hmp_qom_get /build/qemu/src/qom/qom-hmp-cmds.c:66
> 
> Fixes: 89cf4fe34f4

When you fix a bug in a specific commit, please Cc the commit author and
the reviewers, so they have a chance to 1/ review your fix and 2/ learn
from their mistake.

> Reported-by: Euler Robot <euler.robot@huawei.com>
> Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
> ---
>  qom/qom-hmp-cmds.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/qom/qom-hmp-cmds.c b/qom/qom-hmp-cmds.c
> index f704b6949a..3d2a23292d 100644
> --- a/qom/qom-hmp-cmds.c
> +++ b/qom/qom-hmp-cmds.c
> @@ -71,6 +71,7 @@ void hmp_qom_get(Monitor *mon, const QDict *qdict)
>          qobject_unref(str);
>      }
>  
> +    qobject_unref(obj);

The object_resolve_path() documentation is not clear about that...
Can we get the documentation clarified?

>      hmp_handle_error(mon, err);
>  }
>  
>