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

[Alexander Barabash <alexander_barabash@mentor.com>]

On 02/22/2012 07:24 PM, Paolo Bonzini wrote:
> On 02/22/2012 06:22 PM, 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>
>> ---
>>   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<pbonzini@redhat.com>
Sorry, I did not figure out yet how to add the "v2" to the subject line. ))
Alex