From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755877AbZHYSiR (ORCPT ); Tue, 25 Aug 2009 14:38:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755581AbZHYSiQ (ORCPT ); Tue, 25 Aug 2009 14:38:16 -0400 Received: from slowhand.arndnet.de ([88.198.19.76]:41036 "EHLO mail.unitix.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755542AbZHYSiQ (ORCPT ); Tue, 25 Aug 2009 14:38:16 -0400 Message-ID: <4A942F96.7000900@nets.rwth-aachen.de> Date: Tue, 25 Aug 2009 20:38:14 +0200 From: Arnd Hannemann User-Agent: Thunderbird 2.0.0.23 (X11/20090817) MIME-Version: 1.0 To: Jeremy Fitzhardinge CC: Ingo Molnar , Arnd Hannemann , Pekka Enberg , LKML , "hannes@cmpxchg.org" , "torvalds@linux-foundation.org" , "xen-devel@lists.xensource.com" , Benjamin Herrenschmidt Subject: Re: [bisected] 2.6.31 regression: fails to boot as xen guest References: <4A9407B1.6020400@nets.rwth-aachen.de> <84144f020908250929t7d4a74f1n4827de04e5c4c56a@mail.gmail.com> <4A94161A.2020609@nets.rwth-aachen.de> <1251219129.4852.1.camel@penberg-laptop> <4A94242E.30309@nets.rwth-aachen.de> <1251223399.13451.5.camel@penberg-laptop> <4A942BDD.70303@nets.rwth-aachen.de> <20090825182510.GA6903@elte.hu> <4A942DB9.3020209@goop.org> In-Reply-To: <4A942DB9.3020209@goop.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jeremy Fitzhardinge wrote: > On 08/25/09 11:25, Ingo Molnar wrote: >> * Arnd Hannemann wrote: >> >> >>> Pekka Enberg wrote: >>> >>>> On Tue, 2009-08-25 at 19:49 +0200, Arnd Hannemann wrote: >>>> >>>>> Hi Pekka, >>>>> >>>>> Pekka Enberg wrote: >>>>> >>>>>> On Tue, 2009-08-25 at 18:49 +0200, Arnd Hannemann wrote: >>>>>> >>>>>>>> Thanks for doing the bisect! Can we also see your >>>>>>>> .config also? >>>>>>>> >>>>>>> Config for -rc7 is attached. My bisect configs were based >>>>>>> on that >>>>>>> >>>>>> Thanks! While we wait for the Xen people, you can try the >>>>>> following patch to see if we can narrow the bug down to >>>>>> trap_init(). >>>>>> >>>>> Yes seems to be trap_init(). -rc7 with this patch applied >>>>> boots up to the prompt. >>>>> >>>> Thanks for testing! Ingo, what do you think of the following >>>> patch? AFAICT, x86-32 is the only architecture playing with >>>> traps in mem_init() so this should be the safest fix for >>>> 2.6.31. >>>> >>> Hmm, -rc7 + this fix does not work for me :-/ Still hangs before >>> any output... >>> >> does earlyprintk=vga tell you anything about precisely where it >> hangs? >> > > It's a Xen domain, so it should be earlyprintk=xen > > J > Here is the output with earlyprintk=xen and the second patch from pekka applied: (early) [ 0.000000] Initializing CPU#0 (early) [ 0.000000] Checking if this processor honours the WP bit even in supervisor mode...(early) (early) [ 0.000000] BUG: unable to handle kernel (early) NULL pointer dereference(early) at (null) (early) [ 0.000000] IP:(early) [] xen_evtchn_do_upcall+0xd3/0x160 (early) [ 0.000000] *pdpt = 0000000008386001 (early) (early) [ 0.000000] Thread overran stack, or stack corrupted (early) [ 0.000000] Oops: 0000 [#1] (early) SMP (early) (early) [ 0.000000] last sysfs file: (early) [ 0.000000] Modules linked in:(early) (early) [ 0.000000] (early) [ 0.000000] Pid: 0, comm: swapper Not tainted (2.6.31-rc7-pae-um #10) (early) [ 0.000000] EIP: 0061:[] EFLAGS: 00010046 CPU: 0 (early) [ 0.000000] EIP is at xen_evtchn_do_upcall+0xd3/0x160 (early) [ 0.000000] EAX: 00000004 EBX: 00000000 ECX: 00000004 EDX: ffffffff (early) [ 0.000000] ESI: fffffffe EDI: 00000000 EBP: 00000000 ESP: c1413e64 (early) [ 0.000000] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: e021 (early) [ 0.000000] Process swapper (pid: 0, ti=c1412000 task=c13d11a0 task.ti=c1412000) (early) [ 0.000000] Stack: (early) [ 0.000000] f5793000(early) c146d9f0(early) c146d9f0(early) 00000000(early) c1413e9c(early) 00000000(early) 00000000(early) c3a01020(early) (early) [ 0.000000] <0>(early) 00000000(early) eec06067(early) c000cff8(early) 00000000(early) 00000000(early) c10086d7(early) eec06067(early) c000cff8(early) (early) [ 0.000000] <0>(early) f55ff000(early) c000cff8(early) 00000000(early) 00000000(early) c13d7d60(early) c101e021(early) c141e021(early) c10100d8(early) (early) [ 0.000000] Call Trace: (early) [ 0.000000] [] ? xen_do_upcall+0x7/0xc (early) [ 0.000000] [] ? ptep_set_access_flags+0x1/0x80 (early) [ 0.000000] [] ? find_e820_area_size+0x51/0x330 (early) Best regards, Arnd