From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756235AbbCSAXJ (ORCPT ); Wed, 18 Mar 2015 20:23:09 -0400 Received: from mail-we0-f175.google.com ([74.125.82.175]:35975 "EHLO mail-we0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752508AbbCSAXG (ORCPT ); Wed, 18 Mar 2015 20:23:06 -0400 Message-ID: <550A16E6.70001@message-id.googlemail.com> Date: Thu, 19 Mar 2015 01:23:02 +0100 From: Stefan Seyfried User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: Andy Lutomirski CC: Jiri Kosina , Denys Vlasenko , Linus Torvalds , Takashi Iwai , X86 ML , LKML , Tejun Heo Subject: Re: PANIC: double fault, error_code: 0x0 in 4.0.0-rc3-2, kvm related? References: <5505400B.8050300@message-id.googlemail.com> <5509CBF7.3040602@message-id.googlemail.com> <5509F161.3010101@redhat.com> <5509FE69.3060002@message-id.googlemail.com> In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am 19.03.2015 um 00:22 schrieb Andy Lutomirski: > On Wed, Mar 18, 2015 at 3:40 PM, Andy Lutomirski wrote: >> Yes, it's userspace. Thanks for checking, though. > > One more stupid hunch: > > Can you do: > x/21xg ffff8801013d4f58 > > If I counted right, that'll dump task_pt_regs(current). That's all zeroes: crash> x /21xg 0xffff8801013d4f58 0xffff8801013d4f58: 0x0000000000000000 0x0000000000000000 0xffff8801013d4f68: 0x0000000000000000 0x0000000000000000 0xffff8801013d4f78: 0x0000000000000000 0x0000000000000000 0xffff8801013d4f88: 0x0000000000000000 0x0000000000000000 0xffff8801013d4f98: 0x0000000000000000 0x0000000000000000 0xffff8801013d4fa8: 0x0000000000000000 0x0000000000000000 0xffff8801013d4fb8: 0x0000000000000000 0x0000000000000000 0xffff8801013d4fc8: 0x0000000000000000 0x0000000000000000 0xffff8801013d4fd8: 0x0000000000000000 0x0000000000000000 0xffff8801013d4fe8: 0x0000000000000000 0x0000000000000000 0xffff8801013d4ff8: 0x0000000000000000 But maybe you counted wrong (or I'm reading arch/x86/include/asm/processor.h wrong, which is at least as likely...). #define task_pt_regs(tsk) ((struct pt_regs *)(tsk)->thread.sp0 - 1) => I have the task_struct readily available decoded in the crash utility. crash> task, search for thread, in thread: sp0 = 18446612136629993472 crash> eval 18446612136629993472 hexadecimal: ffff8801013d8000 (18014269664677728KB) .... crash> print *(struct pt_regs *)(18446612136629993472 - sizeof(struct pt_regs)) $20 = { r15 = 18446744071585666077, r14 = 16, r13 = 582, r12 = 18446612136629993352, bp = 24, bx = 18446744071585666061, r11 = 582, r10 = 10760856, r9 = 140712613762160, r8 = 140735967861216, ax = 1, cx = 140712476030103, dx = 140712613782304, si = 1, di = 140712589295616, orig_ax = 209, ip = 140712571864823, cs = 51, flags = 582, sp = 140735967860552, ss = 43 } => r15 = ffffffff8168141d r12 = ffff8801013d7f88 bx = ffffffff8168140d r9 = 7ffa355bd470 ip = 7ffa32dc86f7 sp = 7fffa55f1748 looks somehow legit, to my totally untrained eye (ip and sp actually). I'm off to bed now (01:20 around here ;), will be back in about 7 hours. Best regards, Stefan -- Stefan Seyfried Linux Consultant & Developer -- GPG Key: 0x731B665B B1 Systems GmbH Osterfeldstraße 7 / 85088 Vohburg / http://www.b1-systems.de GF: Ralph Dehner / Unternehmenssitz: Vohburg / AG: Ingolstadt,HRB 3537