Re: [PATCH 1/5] Input: ambakmi - Convert to use devm_*()

From	Russell King - ARM Linux <linux@armlinux.org.uk>
Newsgroups	linux.kernel
Subject	Re: [PATCH 1/5] Input: ambakmi - Convert to use devm_*()
Date	2017-03-26 17:00 +0200
Message-ID	<tphOa-1js-3@gated-at.bofh.it> (permalink)
References	<tphEt-1ge-5@gated-at.bofh.it> <tphEt-1ge-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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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.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
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Thread

[PATCH 1/5] Input: ambakmi - Convert to use devm_*() Leo Yan <leo.yan@linaro.org> - 2017-03-26 16:50 +0200
  Re: [PATCH 1/5] Input: ambakmi - Convert to use devm_*() Russell King - ARM Linux <linux@armlinux.org.uk> - 2017-03-26 17:00 +0200
    Re: [PATCH 1/5] Input: ambakmi - Convert to use devm_*() Leo Yan <leo.yan@linaro.org> - 2017-03-26 17:40 +0200

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