From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shuah Khan Subject: Re: [PATCH] power: Change device_wakeup_enable() to check for null dev_name(dev) Date: Sat, 16 Nov 2013 08:28:23 -0700 Message-ID: <52878F17.6020104@samsung.com> References: <1384560238-10708-1-git-send-email-shuah.kh@samsung.com> <4035469.UfR6Rto3I2@vostro.rjw.lan> <5286B95F.4040306@samsung.com> <20131116002501.GA20625@kroah.com> Reply-To: shuah.kh@samsung.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mailout1.w2.samsung.com ([211.189.100.11]:51729 "EHLO usmailout1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752035Ab3KPP2p (ORCPT ); Sat, 16 Nov 2013 10:28:45 -0500 In-reply-to: <20131116002501.GA20625@kroah.com> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Greg KH , anton@enomsg.org, dwmw2@infradead.org Cc: "Rafael J. Wysocki" , len.brown@intel.com, pavel@ucw.cz, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, shuahkhan@gmail.com, stable@vger.kernel.org, Shuah Khan On 11/15/2013 05:25 PM, Greg KH wrote: > On Fri, Nov 15, 2013 at 05:16:31PM -0700, Shuah Khan wrote: >> On 11/15/2013 05:21 PM, Rafael J. Wysocki wrote: >>> On Friday, November 15, 2013 05:03:57 PM Shuah Khan wrote: >>>> device_wakeup_enable() uses dev_name(dev) as the wakeup source name. >>>> When it gets called with a device with its name not yet set, ws structure >>>> with ws->name = NULL gets created. >>>> >>>> When kernel is booted with wakeup_source_activate enabled, it will panic >>>> when the trace point code tries to derefernces ws->name. >>>> >>>> Change device_wakeup_enable() to check for dev_name(dev) null condition >>>> and return -EINVAL to avoid panics when device_wakeup_enable() gets called >>>> before device is fully initialized with its name. >> return -EINVAL; >>> >>> Can you please use WARN_ON(!dev_name(dev)) here? While I agree that it is a >>> bad idea to crash the kernel because dev has no name, that indicates a driver >>> bug that shouldn't be too easy to ignore. >>> >>> Thanks! >>> >> >> Right. ok I will re-cut the patch with WARN_ON and send it. fyi I did >> send fix for the driver (power_supply) as well. >> >> http://www.kernelhub.org/?msg=362354&p=2 > > Why is a driver calling kobject_set_name() instead of device_set_name()? > > Yes, it's really the same thing deep down, but drivers should never care > about a kobject, just 'struct device'. Well, even then it usually > should care about it's type of 'struct device' but that's a different > issue... > > Anyway, not saying your patch is wrong at all, just for the future if > people are looking for code cleanups... > Use of kobject_set_name() did look odd to me. I will fix that for this driver by re-doing the patch while I am it. About the power_supply patch, stable needs fixing as well, and I will have to backport once he fix goes into the mainline. http://www.kernelhub.org/?msg=362354&p=2 as is doesn't apply to 3.10 and 3.11 -- Shuah -- Shuah Khan Senior Linux Kernel Developer - Open Source Group Samsung Research America(Silicon Valley) shuah.kh@samsung.com | (970) 672-0658