From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757213AbZCPIyi (ORCPT ); Mon, 16 Mar 2009 04:54:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753215AbZCPIy3 (ORCPT ); Mon, 16 Mar 2009 04:54:29 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:38911 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753032AbZCPIy2 (ORCPT ); Mon, 16 Mar 2009 04:54:28 -0400 Date: Mon, 16 Mar 2009 09:54:02 +0100 From: Ingo Molnar To: Jeremy Fitzhardinge Cc: "H. Peter Anvin" , Yinghai Lu , Linux Kernel Mailing List Subject: Re: [crash] Re: Latest brk patchset Message-ID: <20090316085402.GC1062@elte.hu> References: <49BC413B.5020104@zytor.com> <49BC4CAC.202@goop.org> <49BC4DB6.9070403@zytor.com> <49BCA03D.3020605@goop.org> <20090315203802.GA14625@elte.hu> <49BD70EF.7010204@goop.org> <20090315212854.GA23960@elte.hu> <49BD8F15.4020301@goop.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <49BD8F15.4020301@goop.org> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Jeremy Fitzhardinge wrote: > Ingo Molnar wrote: >> * Jeremy Fitzhardinge wrote: >> >> >>> Ingo Molnar wrote: >>> >>>> * Jeremy Fitzhardinge wrote: >>>> >>>> >>>>> H. Peter Anvin wrote: >>>>> >>>>>> Well, the semantics are different; the .bss section is zeroed while the >>>>>> brk isn't, and the brk symbols don't necessarily point to the data >>>>>> associated with those particular symbols, unlike (of course) the bss. >>>>>> >>>>>> It's not a big issue, obviously, it just seems cleaner to me that way. >>>>>> >>>>> OK, I just added a couple of changes to: >>>>> >>>>> * make the brk reservation symbols have the form ".brk.NAME" to make >>>>> them inaccessible from C, and to make them look obviously >>>>> different from normal symbols (more like sections, since it is >>>>> their size that's more important than their address) >>>>> * Put all the brk stuff in a .brk section >>>>> * Mention alignment in the comment for the slop space >>>>> >>>>> J >>>>> >>>>> The following changes since commit 1e08816af0bc345995c3f26ce4eaba1171ffb531: >>>>> Ingo Molnar (1): >>>>> Merge branch 'linus' >>>>> >>>>> are available in the git repository at: >>>>> >>>>> git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git push/x86/brk >>>>> >>>> the previous kit in tip:x86/setup-memory is causing crashes. One of >>>> them is: >>>> >>>> init_memory_mapping: 0000000000000000-00000000377fe000 >>>> 0000000000 - 00377fe000 page 4k >>>> Kernel panic - not syncing: Cannot >>>> find space for the kernel page tables Pid: 0, comm: >>>> swapper Not tainted 2.6.29-rc8-tip-02516-g83219b0-dirty #35476 >>>> Call Trace: >>>> [] panic+0x4b/0x100 >>>> [] >>>> init_memory_mapping+0x429/0x430 >>>> [] setup_arch+0x430/0x890 >>>> [] ? lockdep_init_map+0x2e/0x150 >>>> [] ? >>>> __spin_lock_init+0x32/0x60 >>>> [] ? printk+0x20/0x30 >>>> [] start_kernel+0xc6/0x330 >>>> [] >>>> i386_start_kernel+0x41/0x50 >>>> >>>> full crashlog below, config attached. >>>> >>> What branch is this? I'm trying to build with your config with >>> current tip/master w/ tip/x86/setup-memory merged into it, but "make >>> ARCH=i386 oldconfig" is asking me about CONFIG_SMP, which makes me >>> think the config file is incomplete. >>> >> >> just accept the defaults in 'make oldconfig' and you'll get the right >> config. >> > > Got some build failures due to warnings treated as errors. Sorry - you need CONFIG_ALLOW_WARNINGS=y. Indeed my tests can emit !CONFIG_ALLOW_WARNINGS configs. > And the resulting kernel booted fine under qemu with 1Gbyte of > memory. I'll try on real hardware a bit later, but it doesn't > seem like something that should be affected by qemu vs native, > unless it has something to do with the specific e820 map. Note that the crash was reproducible and it very clearly went away when i excluded those commits from tip:master. Ingo