linux-kernel - Re: [PATCH] lib/kobject: put kobject if kobject_add

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Date:	Sat, 25 Jul 2009 14:52:33 +0800
From:	Ming Lei <tom.leiming@...il.com>
To:	Xiaotian Feng <xtfeng@...il.com>
Cc:	Xiaotian Feng <dfeng@...hat.com>, gregkh@...e.de,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] lib/kobject: put kobject if kobject_add_internal fails

2009/7/25 Xiaotian Feng <xtfeng@...il.com>:
>> No, you should fix the 20+ files instead of lib/kobject. One rule should
>> be:
>>
>>             One who allocated kobject should free the kobject,
>> instead of others.
>
>
> kobject_put is not to free the kobject, it's to cleanup the resources
> allocated by kobject_init/add/....
> After kobject_put, we just have a cleanup kobject. The freed action is taken
> by kfree called by who uses kobject,

kobject_put may (but not must) free the kobject, which depends on the kobj_type
passed to  kobject_init_and_add. The .release of the default
kobj_type(dynamic_kobj_ktype) will free the kobject and kobject_put will call
.release.

Even you can make sure _all_ .release of the passed kobj_type does not free
the kobject, you still have the double calling of kobject_put problem,
don't you?

Thanks.

-- 
Lei Ming
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