Return-path: Received: from mail-vw0-f46.google.com ([209.85.212.46]:63896 "EHLO mail-vw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751966Ab1LPONk (ORCPT ); Fri, 16 Dec 2011 09:13:40 -0500 Message-ID: <4EEB521A.70602@lwfinger.net> (sfid-20111216_151401_908907_136BC178) Date: Fri, 16 Dec 2011 08:13:46 -0600 From: Larry Finger MIME-Version: 1.0 To: Johannes Berg CC: Arend van Spriel , "linux-wireless@vger.kernel.org" , "linux-kernel@vger.kernel.org" , John Linville Subject: Re: unexpected taint message References: <4EEB0EFC.5000302@broadcom.com> (sfid-20111216_102800_182196_AFD2D6CF) <1324038636.3429.1.camel@jlt3.sipsolutions.net> <4EEB4D61.80602@lwfinger.net> (sfid-20111216_145414_221850_EED1E4DE) <1324043939.3429.2.camel@jlt3.sipsolutions.net> In-Reply-To: <1324043939.3429.2.camel@jlt3.sipsolutions.net> Content-Type: text/plain; charset=UTF-8; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 12/16/2011 07:58 AM, Johannes Berg wrote: > On Fri, 2011-12-16 at 07:53 -0600, Larry Finger wrote: >> On 12/16/2011 06:30 AM, Johannes Berg wrote: >>> On Fri, 2011-12-16 at 10:27 +0100, Arend van Spriel wrote: >>>> To whoever may know, >>>> >>>> Upon loading our driver module I get the following message: >>>> >>>> kernel: [ 344.805106] Disabling lock debugging due to kernel taint >>>> >>>> What exactly are the criteria for tainting? Our driver locking strategy >>>> is something we want to refactor and having lock debugging during that >>>> transition may be a life safer. >>> >>> cat /proc/sys/kernel/tainted >> >> Please note that Documentation/sysctl/kernel.txt is missing the explanation for >> two bits in the value printed: >> >> 2048 - The system is working around a severe firmware bug. >> 4096 - An out-of-tree module has been loaded. >> >> On my system, bit 4096 is set due to loading the VirtualBox module, which >> disables lock debugging lock debugging. I suspect that loading VMware would >> cause the same condition. > > Hmm. I wish OOT didn't disable lockdep, we do a lot of development with > modules OOT because the turnaround is faster/easier (for not so > experienced developers). Worst case we can patch it out of the base > kernel I guess... Me too. Now I understand John's patch entitled "[RFC] modpost: add option to allow external modules to avoid taint". I doubt that it will be allowed upstream, but I think that I will add it as a local commit. I had failed to notice that the VB module was disabling lock checking, and I ACKed a patch to rtlwifi that triggers a nested lock WARNING. Oh well, at least the bug was not released into the wild yet. Larry