linux-kernel - Re: [PATCH v4 11/20] power_supply: Change ownership from driver to core

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20150226082437.GH6688@x1>
Date:	Thu, 26 Feb 2015 08:24:37 +0000
From:	Lee Jones <lee.jones@...aro.org>
To:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
Cc:	Sebastian Reichel <sre@...nel.org>,
	Dmitry Eremin-Solenikov <dbaryshkov@...il.com>,
	David Woodhouse <dwmw2@...radead.org>,
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Len Brown <lenb@...nel.org>, Jiri Kosina <jkosina@...e.cz>,
	David Herrmann <dh.herrmann@...glemail.com>,
	Cezary Jackiewicz <cezary.jackiewicz@...il.com>,
	Darren Hart <dvhart@...radead.org>,
	Support Opensource <support.opensource@...semi.com>,
	Milo Kim <milo.kim@...com>,
	Julian Andres Klode <jak@...-linux.org>,
	Marc Dietrich <marvin24@....de>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-acpi@...r.kernel.org, linux-input@...r.kernel.org,
	platform-driver-x86@...r.kernel.org,
	patches@...nsource.wolfsonmicro.com, ac100@...ts.launchpad.net,
	linux-tegra@...r.kernel.org, devel@...verdev.osuosl.org,
	Linus Walleij <linus.walleij@...aro.org>,
	Samuel Ortiz <sameo@...ux.intel.com>,
	linux-arm-kernel@...ts.infradead.org,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
	Daniel Mack <daniel@...que.org>,
	Haojian Zhuang <haojian.zhuang@...il.com>,
	Robert Jarzmik <robert.jarzmik@...e.fr>,
	Thomas Gleixner <tglx@...utronix.de>,
	Pavel Machek <pavel@....cz>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	Marek Szyprowski <m.szyprowski@...sung.com>
Subject: Re: [PATCH v4 11/20] power_supply: Change ownership from driver to
 core

On Mon, 23 Feb 2015, Krzysztof Kozlowski wrote:

> Change the ownership of power_supply structure from each driver
> implementing the class to the power supply core.
> 
> The patch changes power_supply_register() function thus all drivers
> implementing power supply class are adjusted.
> 
> Each driver provides the implementation of power supply. However it
> should not be the owner of power supply class instance because it is
> exposed by core to other subsystems with power_supply_get_by_name().
> These other subsystems have no knowledge when the driver will unregister
> the power supply. This leads to several issues when driver is unbound -
> mostly because user of power supply accesses freed memory.
> 
> Instead let the core own the instance of struct 'power_supply'.  Other
> users of this power supply will still access valid memory because it
> will be freed when device reference count reaches 0. Currently this
> means "it will leak" but power_supply_put() call in next patches will
> solve it.
> 
> This solves invalid memory references in following race condition
> scenario:
> 
> Thread 1: charger manager
> Thread 2: power supply driver, used by charger manager
> 
> THREAD 1 (charger manager)         THREAD 2 (power supply driver)
> ==========================         ==============================
> psy = power_supply_get_by_name()
>                                    Driver unbind, .remove
>                                      power_supply_unregister()
>                                      Device fully removed

[...]

>  include/linux/mfd/abx500/ux500_chargalg.h |  11 +-
>  include/linux/mfd/rt5033.h                |   2 +-
>  include/linux/mfd/wm8350/supply.h         |   6 +-

Acked-by: Lee Jones <lee.jones@...aro.org>

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/