From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Vegard Nossum" Subject: Re: linux-next: Tree for July 18: warning at kernel/lockdep.c:2068 trace_hardirqs_on_caller Date: Sun, 20 Jul 2008 00:44:38 +0200 Message-ID: <19f34abd0807191544nfd73be5nf7dde4b61992a7e8@mail.gmail.com> References: <20080718195352.e562a00f.sfr@canb.auug.org.au> <200807190928.33978.m.kozlowski@tuxland.pl> <19f34abd0807190255x304173d4wf2bfabb2d5bce511@mail.gmail.com> <19f34abd0807190559y2fe5ebf9h7095793e82de3122@mail.gmail.com> <20080719221723.GB5578@suse.de> <19f34abd0807191527u61c5ed61kffe2279c8d46915d@mail.gmail.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:cc:in-reply-to:mime-version:content-type :content-transfer-encoding:content-disposition:references; bh=1PWD0z1/m+lOkpqNdSWxNgmUy8s9qMSu8XWT+gBPx08=; b=ODFIzSQO7C6J3oPc0REGgLCVE8zsuH18TCCcCZlzn3CDNHEwajrgpHBZeGLkFrB/S+ gY2iX4c8pVHWiHtXu0evMHBtmc7spcURzjM9qrY9aEOkOIrWswb6vXkBuOgsJv4Zf0hz sMJxt2rCHbHNpdndyUf6dJV8NudnDWmkwiC3s= In-Reply-To: <19f34abd0807191527u61c5ed61kffe2279c8d46915d@mail.gmail.com> Content-Disposition: inline Sender: linux-next-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Greg KH Cc: Mariusz Kozlowski , Dave Hansen , Stephen Rothwell , kernel-testers@vger.kernel.org, linux-next@vger.kernel.org, LKML , Pekka Enberg , Bernhard Walle On Sun, Jul 20, 2008 at 12:27 AM, Vegard Nossum wrote: >>> commit 0e3638d1e04040121af00195f7e4628078246489 >>> Author: Dave Hansen >>> Date: Thu Mar 16 17:30:16 2006 -0800 >>> >>> warn when statically-allocated kobjects are used >>> >>> ..which only exists in -next. Is that just a truly ancient patch, or >>> did somebody forget to adjust their clock? >> >> It is truely a very old patch, that only lives in my tree, and currently >> isn't planned to go to Linus any year soon. >> >> But it has a very long history of living in the -mm tree, and finding >> real bugs, it's just not "safe" enough to go to Linus's tree. Unless >> you think it is? > > Hm. In this case, the patch is not even reporting a problem, it is in > fact in error itself. > > The problem is that it calls kzalloc() before the slab caches have > been set up. (Yes, it's a wonder that nothing crashed.) I can only > suggest the addendum > > if (!slab_is_available()) > return; Well, of course, it's also possible that the e820 code shouldn't be initializing kobjects this early in the first place. firmware_map_add_early() is using bootmem for the allocation. So yes, I guess it should possible to use kobjects here. That said, this code is in fact fairly recent: commit 69ac9cd629ca96e59f34eb4ccd12d00b2c8276a7 Author: Bernhard Walle Date: Fri Jun 27 13:12:54 2008 +0200 sysfs: add /sys/firmware/memmap I'll add the Cc. I still have a feeling that the kobject patch should expect to run even when slab is not available. Vegard -- "The animistic metaphor of the bug that maliciously sneaked in while the programmer was not looking is intellectually dishonest as it disguises that the error is the programmer's own creation." -- E. W. Dijkstra, EWD1036