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

[Paolo Bonzini]

On 02/22/2012 06:22 PM, address@hidden wrote:
> From: Alexander Barabash <address@hidden>
> 
> 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 <address@hidden>
> ---
>  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,

Reviewed-by: Paolo Bonzini <address@hidden>