Date: Sun, 26 Mar 2017 15:50:24 +0100
From: Russell King - ARM Linux <linux@armlinux.org.uk>
To: Leo Yan <leo.yan@linaro.org>
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: <20170326145023.GO7909@n2100.armlinux.org.uk>
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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.

-- 
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