linux-kernel - Re: [PATCH v2] HID: hid-input: Fix accessing freed memory during device disconnect

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Message-id: <55BEF4D3.7050903@samsung.com>
Date:	Mon, 03 Aug 2015 13:57:55 +0900
From:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
To:	Jiri Kosina <jkosina@...e.com>, linux-input@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc:	Dmitry Torokhov <dmitry.torokhov@...il.com>, sre@...nel.org,
	linux-pm@...r.kernel.org, "H.J. Lu" <hjl.tools@...il.com>,
	stable@...r.kernel.org
Subject: Re: [PATCH v2] HID: hid-input: Fix accessing freed memory during
 device disconnect

On 03.08.2015 09:01, Krzysztof Kozlowski wrote:
> During unbinding the driver was dereferencing a pointer to memory
> already freed by power_supply_unregister().
> 
> Driver was freeing its internal description of battery through pointers
> stored in power_supply structure. However, because the core owns the
> power supply instance, after calling power_supply_unregister() this
> memory is freed and the driver cannot access these members.
> 
> Fix this by storing the pointer to internal description of battery in a
> local variable before calling power_supply_unregister(), so the pointer
> remains valid.
> 
> Signed-off-by: Krzysztof Kozlowski <k.kozlowski@...sung.com>
> Reported-by: H.J. Lu <hjl.tools@...il.com>
> Fixes: 297d716f6260 ("power_supply: Change ownership from driver to core")
> Cc: <stable@...r.kernel.org>
> 
> ---
> Changes since v1:
> 1. Re-work idea, use local variable instead of devm-like functions
>    (pointed out by Dmitry Torokhov).
> 2. Adjusted subject and commit message.

I missed the warning:
drivers/hid/hid-input.c:470:11: warning: assignment discards ‘const’
qualifier from pointer target type

I'll fix this and send v3.

Best regards,
Krzysztof

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