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Date:   Tue, 30 Apr 2019 17:08:11 +0200
From:   Petr Mladek <pmladek@suse.com>
To:     "Tobin C. Harding" <tobin@kernel.org>
Cc:     Josh Poimboeuf <jpoimboe@redhat.com>,
        Jiri Kosina <jikos@kernel.org>,
        Miroslav Benes <mbenes@suse.cz>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Joe Lawrence <joe.lawrence@redhat.com>,
        live-patching@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] livepatch: Use correct kobject cleanup function
Message-ID: <20190430150811.4hzhtz4w46o6numh@pathway.suse.cz>
References: <20190430001534.26246-1-tobin@kernel.org>
 <20190430001534.26246-3-tobin@kernel.org>
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On Tue 2019-04-30 10:15:34, Tobin C. Harding wrote:
> The correct cleanup function after a call to kobject_init_and_add() has
> succeeded is kobject_del() _not_ kobject_put().  kobject_del() calls
> kobject_put().

Really? I see only kobject_put(kobj->parent) in kobject_del.
It decreases a reference of the _parent_ object and not
the given one.

Also the section "Kobject removal" in Documentation/kobject.txt
says that kobject_del() is for two-stage removal. kobject_put()
still needs to get called at a later time.

IMHO, this patch causes that kobject_put() would never get called.

That said, we could probably make the removal a bit cleaner
by using kobject_del() in klp_free_patch_start() and
kobject_put() in klp_free_patch_finish(). But I have
to think more about it.

Best Regards,
Petr