From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MARCF-000117-Sq for qemu-devel@nongnu.org; Sat, 30 May 2009 12:14:11 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MARCB-00010E-6c for qemu-devel@nongnu.org; Sat, 30 May 2009 12:14:11 -0400 Received: from [199.232.76.173] (port=39975 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MARCA-00010B-VA for qemu-devel@nongnu.org; Sat, 30 May 2009 12:14:07 -0400 Received: from mail-bw0-f175.google.com ([209.85.218.175]:41876) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1MARCA-0001A8-Fq for qemu-devel@nongnu.org; Sat, 30 May 2009 12:14:06 -0400 Received: by bwz23 with SMTP id 23so5955893bwz.34 for ; Sat, 30 May 2009 09:14:04 -0700 (PDT) MIME-Version: 1.0 Date: Sat, 30 May 2009 18:14:04 +0200 Message-ID: <19f34abd0905300914m7f45e2d6u15f70fcb7cad600a@mail.gmail.com> From: Vegard Nossum Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Rare linux boot failures ("divide error") with 0.9.1 List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Hi, I am writing because I've encountered a particular (but very rare) error that sometimes happen with qemu. I am booting the linux kernel and suddenly, I get a flood of messages like this: [ 2.335001] RIP [] oops_end+0x6b/0xe0 [ 2.335001] RSP [ 2.335001] divide error: 0000 [#61] SMP [ 2.335001] last sysfs file: [ 2.335001] CPU 0 [ 2.335001] Modules linked in: [ 2.335001] Pid: 1, comm: swapper Tainted: G D 2.6.30-rc5 #401 [ 2.335001] RIP: 0010:[] [] oops_end+0x6b/0xe0 [ 2.335001] RSP: 0018:ffff880001a49328 EFLAGS: 00000292 [ 2.335001] RAX: 0000000000000000 RBX: ffff880001a49478 RCX: 0000000000000000 [ 2.335001] RDX: 000000000000d7d7 RSI: 0000000000000046 RDI: 0000000000000007 [ 2.335001] RBP: ffff880001a49348 R08: 0000000000000000 R09: 0000000000000000 [ 2.335001] R10: 0000000000000000 R11: 0000000000000002 R12: 0000000000000292 [ 2.335001] R13: 000000000000000b R14: 0000000000000292 R15: 0000000000000008 [ 2.335001] FS: 0000000000000000(0000) GS:ffff880001a4d000(0000) knlGS:0000000000000000 [ 2.335001] CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b [ 2.335001] CR2: ffff8800078000d8 CR3: 0000000001001000 CR4: 00000000000006e0 [ 2.335001] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 2.335001] DR3: 0000000000000000 DR6: 0000000000004000 DR7: 0000000000000000 [ 2.335001] Process swapper (pid: 1, threadinfo ffff8800078c2000, task ffff8800078c8000) [ 2.335001] Stack: [ 2.335001] ffff880001a49348 ffff880001a49478 0000000000000000 ffffffff817525b5 [ 2.335001] ffff880001a49378 ffffffff8100fb26 ffff8800078c8000 0000000000000000 [ 2.335001] ffff880001a49478 0000000000000000 ffff880001a493c8 ffffffff815d3ea6 [ 2.335001] Call Trace: [ 2.335001] Code: c7 05 d6 86 23 00 ff ff ff ff e8 51 28 a7 ff 8b 05 5f 1c 3a 00 83 e8 01 85 c0 89 05 54 1c 3a 00 75 06 fe 05 44 1c 3a 00 41 54 9d f0 27 a7 ff 45 85 ed 74 43 65 48 8b 04 25 a8 b4 00 00 48 63 So apparently we got a divide error, but the instruction in question (as reported by the CPU) is not a division: Code starting with the faulting instruction =========================================== 0: e8 f0 27 a7 ff callq 0xffffffffffa727f5 5: 45 85 ed test %r13d,%r13d I've seen this maybe 4-5 times out of hundreds of bootups, and the next time I try to run it, everything works fine (this is also why I can never capture the _first_ such message; I'm not expecting it and therefore not logging it), with no change in image, disk, settings, or command line. I am using qemu version 0.9.1 on x86_64 (emulating x86_64 as well): $ rpm -q -i qemu Name : qemu Relocations: (not relocatable) Version : 0.9.1 Vendor: Fedora Project Release : 12.fc10 Build Date: Sun 11 Jan 2009 06:48:00 PM CET Install Date: Sun 26 Apr 2009 03:30:56 PM CEST Build Host: xenbuilder4.fedora.phx.redhat.com Group : Development/Tools Source RPM: qemu-0.9.1-12.fc10.src.rpm Kind regards, Vegard