Re: [Qemu-devel] [PATCH] qom: In function object_set_link_property(), first call object_ref(), then object_unref().

[Anthony Liguori <aliguori@us.ibm.com>]

On 02/22/2012 11:22 AM, alexander_barabash@mentor.com wrote:
> From: Alexander Barabash<alexander_barabash@mentor.com>
>
> In the old implementation, if the new value of the property links
> to the same object, as the old value, that object is first unref-ed,
> and then ref-ed. This leads to unintended deinitialization of that object.
>
> In the new implementation, this is fixed.
>
> Signed-off-by: Alexander Barabash<alexander_barabash@mentor.com>

Applied.  Thanks.

Regards,

Anthony Liguori

> ---
>   qom/object.c |   11 +++++++----
>   1 files changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/qom/object.c b/qom/object.c
> index 941c291..e6591e1 100644
> --- a/qom/object.c
> +++ b/qom/object.c
> @@ -892,6 +892,7 @@ static void object_set_link_property(Object *obj, Visitor *v, void *opaque,
>                                        const char *name, Error **errp)
>   {
>       Object **child = opaque;
> +    Object *old_target;
>       bool ambiguous = false;
>       const char *type;
>       char *path;
> @@ -901,10 +902,8 @@ static void object_set_link_property(Object *obj, Visitor *v, void *opaque,
>
>       visit_type_str(v,&path, name, errp);
>
> -    if (*child) {
> -        object_unref(*child);
> -        *child = NULL;
> -    }
> +    old_target = *child;
> +    *child = NULL;
>
>       if (strcmp(path, "") != 0) {
>           Object *target;
> @@ -930,6 +929,10 @@ static void object_set_link_property(Object *obj, Visitor *v, void *opaque,
>       }
>
>       g_free(path);
> +
> +    if (old_target != NULL) {
> +        object_unref(old_target);
> +    }
>   }
>
>   void object_property_add_link(Object *obj, const char *name,