linux-kernel - Re: [PATCH v2 2/2] power: charger-manager: Avoid recursive thermal get

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] [day] [month] [year] [list]

Message-ID: <20141027183232.GE10897@earth.universe>
Date:	Mon, 27 Oct 2014 19:32:33 +0100
From:	Sebastian Reichel <sre@...nel.org>
To:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
Cc:	Dmitry Eremin-Solenikov <dbaryshkov@...il.com>,
	David Woodhouse <dwmw2@...radead.org>,
	Myungjoo Ham <myungjoo.ham@...sung.com>,
	Anton Vorontsov <anton@...msg.org>,
	Jonghwa Lee <jonghwa3.lee@...sung.com>,
	Chanwoo Choi <cw00.choi@...sung.com>, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Kyungmin Park <kyungmin.park@...sung.com>,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
Subject: Re: [PATCH v2 2/2] power: charger-manager: Avoid recursive thermal
 get_temp call

Hi,

On Tue, Oct 07, 2014 at 05:47:37PM +0200, Krzysztof Kozlowski wrote:
> The charger manager supports POWER_SUPPLY_PROP_TEMP property and acts
> as a thermal zone if any of these conditions match:
> 1. Fuel gauge used by charger manager supports POWER_SUPPLY_PROP_TEMP.
> 2. 'cm-thermal-zone' property is present in DTS (then it will supersede
>    the fuel gauge temperature property).
> 
> However in case 1 (fuel gauge reports temperature and 'cm-thermal-zone'
> is not set) the charger manager forwards its get_temp calls to fuel
> gauge thermal zone.
> 
> This leads to reporting by lockdep a false positive deadlock for thermal
> zone's mutex because of nested calls to thermal_zone_get_temp(). This is
> false positive because these are different mutexes: one for charger
> manager thermal zone and second for fuel gauge thermal zone.
> 
> Get rid of false lockdep alert and recursive call by setting
> 'no_thermal' property for this power supply class. The thermal zone for
> charger manager won't be created (user space does not use it anyway).

also pulled into next, will also be included in 3.18-rc pull request.

-- Sebastian

Download attachment "signature.asc" of type "application/pgp-signature" (820 bytes)