Date: Sun, 26 Mar 2017 23:23:54 +0800
From: Leo Yan <leo.yan@linaro.org>
To: Russell King - ARM Linux <linux@armlinux.org.uk>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Alessandro Zummo <a.zummo@towertech.it>,
        Alexandre Belloni <alexandre.belloni@free-electrons.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        Baptiste Reynal <b.reynal@virtualopensystems.com>,
        Alex Williamson <alex.williamson@redhat.com>,
        Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>,
        linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
        rtc-linux@googlegroups.com, linux-arm-kernel@lists.infradead.org,
        kvm@vger.kernel.org, alsa-devel@alsa-project.org
Subject: Re: [PATCH 1/5] Input: ambakmi - Convert to use devm_*()
Message-ID: <20170326152354.GA11555@leoy-linaro>
References: <1490539314-9681-1-git-send-email-leo.yan@linaro.org>
 <1490539314-9681-2-git-send-email-leo.yan@linaro.org>
 <20170326145023.GO7909@n2100.armlinux.org.uk>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20170326145023.GO7909@n2100.armlinux.org.uk>
User-Agent: Mutt/1.5.24 (2015-08-30)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 988
Lines: 27

On Sun, Mar 26, 2017 at 03:50:24PM +0100, Russell King - ARM Linux wrote:
> On Sun, Mar 26, 2017 at 10:41:50PM +0800, Leo Yan wrote:
> > Convert driver to use devm_*() APIs so rely on driver model core layer
> > to manage resources. This eliminates error path boilerplate and makes
> > code neat.
> > 
> > This patch also fixes the memory leakage for 'kmi->io' when remove
> > module.
> 
> No, it is not leaked, in fact, your patch introduces a use-after-free
> bug.
> 
> kmi->io is of type "struct serio", and this structure has an embedded
> "struct device".  The lifetime of any structure containing a "struct
> device" is controlled by the lifetime of the struct device.
> 
> Once serio_register_port() has been called on it, it is up to the
> serio layer to free this structure.
> 
> Therefore, your patch creates a bug, and so it gets a NAK.  There is no
> resource leakage here.

Thanks for reviewing. Now I understood and please ignore this patch
and patch 0005.

Thanks,
Leo Yan