From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760006AbaKAAdL (ORCPT ); Fri, 31 Oct 2014 20:33:11 -0400 Received: from ozlabs.org ([103.22.144.67]:58037 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753430AbaKAAdI (ORCPT ); Fri, 31 Oct 2014 20:33:08 -0400 From: Rusty Russell To: Andy Lutomirski , Thomas Gleixner , X86 ML , Ingo Molnar , "H. Peter Anvin" Cc: Sebastian Lackner , Anish Bhatt , "linux-kernel\@vger.kernel.org" , Chuck Ebbert , Andy Lutomirski Subject: Re: [PATCH v4 0/2] x86_64,entry: Clear NT on entry and speed up switch_to In-Reply-To: References: User-Agent: Notmuch/0.17 (http://notmuchmail.org) Emacs/24.3.1 (x86_64-pc-linux-gnu) Date: Sat, 01 Nov 2014 10:50:39 +1030 Message-ID: <877fzf4vqg.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Andy Lutomirski writes: > Anish Bhatt noticed that user programs can set RFLAGS.NT before > syscall or sysenter, and the kernel entry code doesn't filter out > NT. This causes kernel C code and, depending on thread flags, the > exit slow path to run with NT set. OK, this causes oopsen as a guest under kvm for me. Details below: commit 8c7aa698baca5e8f1ba9edb68081f1e7a1abf455 Author: Andy Lutomirski Date: Wed Oct 1 11:49:04 2014 -0700 x86_64, entry: Filter RFLAGS.NT on entry from userspace Some dmesg: [ 0.820982] serio: i8042 KBD port at 0x60,0x64 irq 1 [ 0.822118] serio: i8042 AUX port at 0x60,0x64 irq 12 [ 0.824445] mousedev: PS/2 mouse device common for all mice [ 0.827262] input: AT Translated Set 2 keyboard as /devices/platform/i8042/serio0/input/input1 [ 0.830249] rtc_cmos 00:00: RTC can wake from S4 [ 0.831830] rtc_cmos 00:00: rtc core: registered rtc_cmos as rtc0 [ 0.833314] rtc_cmos 00:00: alarms up to one day, 114 bytes nvram, hpet irqs [ 0.835128] device-mapper: uevent: version 1.0.3 [ 0.836526] device-mapper: ioctl: 4.27.0-ioctl (2013-10-30) initialised: dm-devel@redhat.com [ 0.838566] TCP: cubic registered [ 0.839891] NET: Registered protocol family 10 [ 0.841868] NET: Registered protocol family 17 [ 0.843005] Key type dns_resolver registered [ 0.845481] registered taskstats version 1 [ 0.847120] kworker/u2:2 (48) used greatest stack depth: 14400 bytes left [ 0.849147] kworker/u2:3 (50) used greatest stack depth: 14048 bytes left [ 0.850779] Key type trusted registered [ 0.853360] Key type encrypted registered [ 0.855561] AppArmor: AppArmor sha1 policy hashing enabled [ 0.856768] cryptomgr_probe (63) used greatest stack depth: 13712 bytes left [ 0.858156] evm: HMAC attrs: 0x1 [ 0.859577] Magic number: 2:172:455 [ 0.860833] rtc_cmos 00:00: setting system clock to 2014-10-31 23:26:48 UTC (1414798008) [ 0.862465] BIOS EDD facility v0.16 2004-Jun-25, 0 devices found [ 0.863663] EDD information not available. [ 0.964548] ata2.00: ATAPI: QEMU DVD-ROM, 2.1.0, max UDMA/100 [ 0.966081] ata2.00: configured for MWDMA2 [ 0.968174] scsi 1:0:0:0: CD-ROM QEMU QEMU DVD-ROM 2.1. PQ: 0 ANSI: 5 [ 0.977913] sr 1:0:0:0: [sr0] scsi3-mmc drive: 4x/4x cd/rw xa/form2 tray [ 0.978861] cdrom: Uniform CD-ROM driver Revision: 3.20 [ 0.981138] sr 1:0:0:0: Attached scsi generic sg0 type 5 [ 0.982634] md: Waiting for all devices to be available before autodetect [ 0.986583] md: If you don't use raid, use raid=noautodetect [ 0.990236] md: Autodetecting RAID arrays. [ 0.991035] md: Scanned 0 and added 0 devices. [ 0.991815] md: autorun ... [ 0.992215] md: ... autorun DONE. [ 0.994068] EXT3-fs (vda1): error: couldn't mount because of unsupported optional features (240) [ 0.996331] EXT4-fs (vda1): couldn't mount as ext2 due to feature incompatibilities [ 1.003145] EXT4-fs (vda1): mounted filesystem with ordered data mode. Opts: (null) [ 1.006600] VFS: Mounted root (ext4 filesystem) readonly on device 253:1. [ 1.010007] devtmpfs: mounted [ 1.011632] debug: unmapping init [mem 0xffffffff81d2b000-0xffffffff81e6ffff] [ 1.012631] Write protecting the kernel read-only data: 12288k [ 1.013571] debug: unmapping init [mem 0xffff88000170d000-0xffff8800017fffff] [ 1.014639] debug: unmapping init [mem 0xffff880001b21000-0xffff880001bfffff] [ 1.123201] random: init urandom read with 8 bits of entropy available [ 1.126953] BUG: unable to handle kernel paging request at ffff88001da4c018 [ 1.128482] IP: [] ia32_sysenter_target+0x4d/0x5e [ 1.129513] PGD 2d6c067 PUD 2d6d067 PMD 1fdf4067 PTE 800000001da4c060 [ 1.129513] Oops: 0000 [#1] SMP DEBUG_PAGEALLOC [ 1.129513] Modules linked in: [ 1.129513] CPU: 0 PID: 69 Comm: init Not tainted 3.17.0-rc7+ #245 [ 1.129513] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_171129-lamiak 04/01/2014 [ 1.129513] task: ffff88001da08000 ti: ffff88001da48000 task.ti: ffff88001da48000 [ 1.129513] RIP: 0010:[] [] ia32_sysenter_target+0x4d/0x5e [ 1.129513] RSP: 0018:ffff88001da4bf88 EFLAGS: 00010296 [ 1.129513] RAX: 0000000000000137 RBX: 00000000f754e730 RCX: 000000000000000c [ 1.129513] RDX: 00000000f7711000 RSI: 0000000000000000 RDI: 00000000f77c3040 [ 1.129513] RBP: 00000000ffca97c8 R08: ffffffff8138aa0b R09: 00000000ffcaba58 [ 1.129513] R10: 00000000f77a1b70 R11: 0000000000000000 R12: 0000000000000000 [ 1.129513] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 1.129513] FS: 0000000000000000(0000) GS:ffff88001fa00000(0063) knlGS:00000000f754e6c0 [ 1.129513] CS: 0010 DS: 002b ES: 002b CR0: 000000008005003b [ 1.129513] CR2: ffff88001da4c018 CR3: 000000001da2c000 CR4: 00000000000006f0 [ 1.129513] Stack: [ 1.129513] 0000000000000000 0000000000000000 00000000ffcaba58 ffffffff8138aa0b [ 1.129513] 0000000000000137 000000000000000c 00000000f7711000 0000000000000000 [ 1.129513] 00000000f77c3040 0000000000000137 00000000f77a1b70 0000000000000023 [ 1.129513] Call Trace: [ 1.129513] [] ? trace_hardirqs_on_thunk+0x3a/0x3f [ 1.129513] Code: c0 41 52 50 fc 48 83 ec 48 48 89 7c 24 40 48 89 74 24 38 48 89 54 24 30 48 89 4c 24 28 48 89 44 24 20 66 66 90 8b 6d 00 66 66 90 84 24 90 00 00 00 00 40 00 00 0f 85 2f 01 00 00 83 8c 24 8c [ 1.129513] RIP [] ia32_sysenter_target+0x4d/0x5e [ 1.129513] RSP [ 1.129513] CR2: ffff88001da4c018 [ 1.129513] ---[ end trace 7d7a8bfdc14fe3bb ]--- [ 1.129513] BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:41 [ 1.129513] in_atomic(): 0, irqs_disabled(): 1, pid: 69, name: init [ 1.129513] INFO: lockdep is turned off. [ 1.129513] irq event stamp: 62 [ 1.129513] hardirqs last enabled at (61): [] retint_swapgs+0xe/0x13 [ 1.129513] hardirqs last disabled at (62): [] error_sti+0x5/0x6 [ 1.129513] softirqs last enabled at (0): [] copy_process.part.30+0x5b8/0x1c70 [ 1.129513] softirqs last disabled at (0): [< (null)>] (null) [ 1.129513] CPU: 0 PID: 69 Comm: init Tainted: G D 3.17.0-rc7+ #245 [ 1.129513] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_171129-lamiak 04/01/2014 [ 1.129513] 0000000000000009 ffff88001da4bc08 ffffffff816fbd34 ffff88001f7d35d8 [ 1.129513] ffff88001da4bc18 ffffffff8107d181 ffff88001da4bc38 ffffffff81702314 [ 1.129513] ffff88001da08000 ffff88001da08000 ffff88001da4bc58 ffffffff81067464 [ 1.129513] Call Trace: [ 1.129513] [] dump_stack+0x4d/0x66 [ 1.129513] [] __might_sleep+0xf1/0x120 [ 1.129513] [] down_read+0x24/0x70 [ 1.129513] [] exit_signals+0x24/0x130 [ 1.129513] [] do_exit+0xb3/0xbd0 [ 1.129513] [] ? kmsg_dump+0x108/0x120 [ 1.129513] [] ? kmsg_dump+0x22/0x120 [ 1.129513] [] oops_end+0x8b/0xd0 [ 1.129513] [] no_context+0x12c/0x380 [ 1.129513] [] ? _raw_spin_unlock+0x27/0x40 [ 1.129513] [] ? do_read_fault.isra.77+0xd5/0x2c0 [ 1.129513] [] __bad_area_nosemaphore+0x85/0x210 [ 1.129513] [] bad_area_nosemaphore+0x13/0x20 [ 1.129513] [] __do_page_fault+0xd6/0x5d0 [ 1.129513] [] ? __do_page_fault+0x192/0x5d0 [ 1.129513] [] ? up_read+0x1f/0x40 [ 1.129513] [] ? __do_page_fault+0x294/0x5d0 [ 1.129513] [] ? trace_hardirqs_off_thunk+0x3a/0x3c [ 1.129513] [] do_page_fault+0xc/0x10 [ 1.129513] [] page_fault+0x22/0x30 [ 1.129513] [] ? trace_hardirqs_on_thunk+0x3a/0x3f [ 1.129513] [] ? ia32_sysenter_target+0x4d/0x5e [ 1.129513] [] ? retint_swapgs+0xe/0x13 [ 1.129513] [] ? trace_hardirqs_on_thunk+0x3a/0x3f [ 1.217584] init (69) used greatest stack depth: 13528 bytes left [ 1.229190] BUG: unable to handle kernel paging request at ffff88001da7c018 [ 1.230520] IP: [] ia32_sysenter_target+0x4d/0x5e [ 1.231890] PGD 2d6c067 PUD 2d6d067 PMD 1fdf4067 PTE 800000001da7c060 [ 1.232181] Oops: 0000 [#2] SMP DEBUG_PAGEALLOC [ 1.232181] Modules linked in: [ 1.232181] CPU: 0 PID: 71 Comm: init Tainted: G D 3.17.0-rc7+ #245 [ 1.232181] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_171129-lamiak 04/01/2014 [ 1.232181] task: ffff88001d9f2110 ti: ffff88001da78000 task.ti: ffff88001da78000 [ 1.232181] RIP: 0010:[] [] ia32_sysenter_target+0x4d/0x5e [ 1.232181] RSP: 0018:ffff88001da7bf88 EFLAGS: 00010296 [ 1.232181] RAX: 0000000000000137 RBX: 00000000f754e730 RCX: 000000000000000c [ 1.232181] RDX: 00000000f7711000 RSI: 0000000000000000 RDI: 00000000f77c3040 [ 1.232181] RBP: 00000000ffca97c8 R08: ffffffff8138aa0b R09: 0000000000000000 [ 1.232181] R10: 00000000f77a1b70 R11: 0000000000000000 R12: 0000000000000000 [ 1.232181] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 1.232181] FS: 0000000000000000(0000) GS:ffff88001fa00000(0063) knlGS:00000000f754e6c0 [ 1.232181] CS: 0010 DS: 002b ES: 002b CR0: 000000008005003b [ 1.232181] CR2: ffff88001da7c018 CR3: 000000001da5e000 CR4: 00000000000006f0 [ 1.232181] Stack: [ 1.232181] 0000000000000000 0000000000000000 0000000000000000 ffffffff8138aa0b [ 1.232181] 0000000000000137 000000000000000c 00000000f7711000 0000000000000000 [ 1.232181] 00000000f77c3040 0000000000000137 00000000f77a1b70 0000000000000023 [ 1.232181] Call Trace: [ 1.232181] [] ? trace_hardirqs_on_thunk+0x3a/0x3f [ 1.232181] Code: c0 41 52 50 fc 48 83 ec 48 48 89 7c 24 40 48 89 74 24 38 48 89 54 24 30 48 89 4c 24 28 48 89 44 24 20 66 66 90 8b 6d 00 66 66 90 84 24 90 00 00 00 00 40 00 00 0f 85 2f 01 00 00 83 8c 24 8c [ 1.232181] RIP [] ia32_sysenter_target+0x4d/0x5e [ 1.232181] RSP [ 1.232181] CR2: ffff88001da7c018 [ 1.232181] ---[ end trace 7d7a8bfdc14fe3bc ]--- [ 1.265113] BUG: unable to handle kernel paging request at ffff88001da84018 [ 1.266545] IP: [] ia32_sysenter_target+0x4d/0x5e [ 1.267854] PGD 2d6c067 PUD 2d6d067 PMD 1fdf4067 PTE 800000001da84060 [ 1.268444] Oops: 0000 [#3] SMP DEBUG_PAGEALLOC [ 1.268444] Modules linked in: [ 1.268444] CPU: 0 PID: 72 Comm: init Tainted: G D 3.17.0-rc7+ #245 [ 1.268444] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_171129-lamiak 04/01/2014 [ 1.268444] task: ffff88001d9f4220 ti: ffff88001da80000 task.ti: ffff88001da80000 [ 1.268444] RIP: 0010:[] [] ia32_sysenter_target+0x4d/0x5e [ 1.268444] RSP: 0018:ffff88001da83f88 EFLAGS: 00010296 [ 1.268444] RAX: 0000000000000137 RBX: 00000000f754e730 RCX: 000000000000000c [ 1.268444] RDX: 00000000f7711000 RSI: 0000000000000000 RDI: 00000000f77c3040 [ 1.268444] RBP: 00000000ffca97c8 R08: ffffffff8138aa0b R09: 0000000000000000 [ 1.268444] R10: 00000000f77a1b70 R11: 0000000000000000 R12: 0000000000000000 [ 1.268444] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 1.268444] FS: 0000000000000000(0000) GS:ffff88001fa00000(0063) knlGS:00000000f754e6c0 [ 1.268444] CS: 0010 DS: 002b ES: 002b CR0: 000000008005003b [ 1.268444] CR2: ffff88001da84018 CR3: 000000001da5f000 CR4: 00000000000006f0 [ 1.268444] Stack: [ 1.268444] 0000000000000000 0000000000000000 0000000000000000 ffffffff8138aa0b [ 1.268444] 0000000000000137 000000000000000c 00000000f7711000 0000000000000000 [ 1.268444] 00000000f77c3040 0000000000000137 00000000f77a1b70 0000000000000023 [ 1.268444] Call Trace: [ 1.268444] [] ? trace_hardirqs_on_thunk+0x3a/0x3f [ 1.268444] Code: c0 41 52 50 fc 48 83 ec 48 48 89 7c 24 40 48 89 74 24 38 48 89 54 24 30 48 89 4c 24 28 48 89 44 24 20 66 66 90 8b 6d 00 66 66 90 84 24 90 00 00 00 00 40 00 00 0f 85 2f 01 00 00 83 8c 24 8c [ 1.268444] RIP [] ia32_sysenter_target+0x4d/0x5e [ 1.268444] RSP [ 1.268444] CR2: ffff88001da84018 [ 1.268444] ---[ end trace 7d7a8bfdc14fe3bd ]--- [ 1.301978] init: Error while reading from descriptor: Bad file descriptor [ 1.303740] init: hostname main process (69) killed by KILL signal [ 1.306985] init: hwclock main process (71) killed by KILL signal [ 1.309804] init: ureadahead main process (72) killed by KILL signal [ 1.322693] BUG: unable to handle kernel paging request at ffff88001daa4018 [ 1.324040] IP: [] ia32_sysenter_target+0x4d/0x5e [ 1.324040] PGD 2d6c067 PUD 2d6d067 PMD 1fdf4067 PTE 800000001daa4060 [ 1.324040] Oops: 0000 [#4] SMP DEBUG_PAGEALLOC [ 1.324040] Modules linked in: [ 1.324040] CPU: 0 PID: 75 Comm: init Tainted: G D 3.17.0-rc7+ #245 [ 1.324040] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_171129-lamiak 04/01/2014 [ 1.324040] task: ffff88001d9f2110 ti: ffff88001daa0000 task.ti: ffff88001daa0000 [ 1.324040] RIP: 0010:[] [] ia32_sysenter_target+0x4d/0x5e [ 1.324040] RSP: 0018:ffff88001daa3f88 EFLAGS: 00010296 [ 1.324040] RAX: 0000000000000137 RBX: 00000000f754e730 RCX: 000000000000000c [ 1.324040] RDX: 00000000f7711000 RSI: 0000000000000000 RDI: 00000000f77c3040 [ 1.324040] RBP: 00000000ffca97c8 R08: ffffffff8138aa0b R09: 0000000000000000 [ 1.324040] R10: 00000000f77a1b70 R11: 0000000000000000 R12: 0000000000000000 [ 1.324040] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 1.324040] FS: 0000000000000000(0000) GS:ffff88001fa00000(0063) knlGS:00000000f754e6c0 [ 1.324040] CS: 0010 DS: 002b ES: 002b CR0: 000000008005003b [ 1.324040] CR2: ffff88001daa4018 CR3: 000000001da6e000 CR4: 00000000000006f0 [ 1.324040] Stack: [ 1.324040] 0000000000000000 0000000000000000 0000000000000000 ffffffff8138aa0b [ 1.324040] 0000000000000137 000000000000000c 00000000f7711000 0000000000000000 [ 1.324040] 00000000f77c3040 0000000000000137 00000000f77a1b70 0000000000000023 [ 1.324040] Call Trace: [ 1.324040] [] ? trace_hardirqs_on_thunk+0x3a/0x3f [ 1.324040] Code: c0 41 52 50 fc 48 83 ec 48 48 89 7c 24 40 48 89 74 24 38 48 89 54 24 30 48 89 4c 24 28 48 89 44 24 20 66 66 90 8b 6d 00 66 66 90 84 24 90 00 00 00 00 40 00 00 0f 85 2f 01 00 00 83 8c 24 8c [ 1.324040] RIP [] ia32_sysenter_target+0x4d/0x5e [ 1.324040] RSP [ 1.324040] CR2: ffff88001daa4018 [ 1.324040] ---[ end trace 7d7a8bfdc14fe3be ]--- [ 1.372657] plymouthd (70) used greatest stack depth: 13256 bytes left [ 1.374306] init: Error while reading from descriptor: Bad file descriptor [ 1.376348] init: mountall main process (75) killed by KILL signal [ 1.386907] sh (76) used greatest stack depth: 13208 bytes left [ 1.388173] tsc: Refined TSC clocksource calibration: 2594.100 MHz [ 1.390528] BUG: unable to handle kernel paging request at ffff88001daa4018 [ 1.392121] IP: [] ia32_sysenter_target+0x4d/0x5e [ 1.392121] PGD 2d6c067 PUD 2d6d067 PMD 1fdf4067 PTE 800000001daa4060 [ 1.392121] Oops: 0000 [#5] SMP DEBUG_PAGEALLOC [ 1.392121] Modules linked in: [ 1.392121] CPU: 0 PID: 78 Comm: init Tainted: G D 3.17.0-rc7+ #245 [ 1.392121] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_171129-lamiak 04/01/2014 [ 1.392121] task: ffff88001da0a110 ti: ffff88001daa0000 task.ti: ffff88001daa0000 [ 1.392121] RIP: 0010:[] [] ia32_sysenter_target+0x4d/0x5e [ 1.392121] RSP: 0018:ffff88001daa3f88 EFLAGS: 00010296 [ 1.392121] RAX: 0000000000000137 RBX: 00000000f754e730 RCX: 000000000000000c [ 1.392121] RDX: 00000000f7711000 RSI: 0000000000000000 RDI: 00000000f77c3040 [ 1.392121] RBP: 00000000ffca97c8 R08: ffffffff8138aa0b R09: 0000000000000000 [ 1.392121] R10: 00000000f77a1b70 R11: 0000000000000000 R12: 0000000000000000 [ 1.392121] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 1.392121] FS: 0000000000000000(0000) GS:ffff88001fa00000(0063) knlGS:00000000f754e6c0 [ 1.392121] CS: 0010 DS: 002b ES: 002b CR0: 000000008005003b [ 1.392121] CR2: ffff88001daa4018 CR3: 000000001da27000 CR4: 00000000000006f0 [ 1.392121] Stack: [ 1.392121] 0000000000000000 0000000000000000 0000000000000000 ffffffff8138aa0b [ 1.392121] 0000000000000137 000000000000000c 00000000f7711000 0000000000000000 [ 1.392121] 00000000f77c3040 0000000000000137 00000000f77a1b70 0000000000000023 [ 1.392121] Call Trace: [ 1.392121] [] ? trace_hardirqs_on_thunk+0x3a/0x3f [ 1.392121] Code: c0 41 52 50 fc 48 83 ec 48 48 89 7c 24 40 48 89 74 24 38 48 89 54 24 30 48 89 4c 24 28 48 89 44 24 20 66 66 90 8b 6d 00 66 66 90 84 24 90 00 00 00 00 40 00 00 0f 85 2f 01 00 00 83 8c 24 8c [ 1.392121] RIP [] ia32_sysenter_target+0x4d/0x5e [ 1.392121] RSP [ 1.392121] CR2: ffff88001daa4018 [ 1.392121] ---[ end trace 7d7a8bfdc14fe3bf ]--- [ 1.436568] BUG: unable to handle kernel paging request at ffff88001da4c018 [ 1.438056] IP: [] ia32_sysenter_target+0x4d/0x5e [ 1.439308] PGD 2d6c067 PUD 2d6d067 PMD 1fdf4067 PTE 800000001da4c060 [ 1.440088] Oops: 0000 [#6] SMP DEBUG_PAGEALLOC [ 1.440088] Modules linked in: [ 1.440088] CPU: 0 PID: 73 Comm: plymouthd Tainted: G D 3.17.0-rc7+ #245 [ 1.440088] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_171129-lamiak 04/01/2014 [ 1.440088] task: ffff88001d9f0000 ti: ffff88001da48000 task.ti: ffff88001da48000 [ 1.440088] RIP: 0010:[] [] ia32_sysenter_target+0x4d/0x5e [ 1.440088] RSP: 0018:ffff88001da4bf88 EFLAGS: 00010296 [ 1.440088] RAX: 0000000000000066 RBX: 0000000000000005 RCX: 00000000ffdc3810 [ 1.440088] RDX: 000000000a048bd0 RSI: 000000000a048ca0 RDI: 0000000000000000 [ 1.440088] RBP: 000000000a048c58 R08: 0000000000000000 R09: 0000000000000000 [ 1.440088] R10: 00000000f775ab70 R11: 0000000000000000 R12: 0000000000000000 [ 1.440088] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 1.440088] FS: 0000000000000000(0000) GS:ffff88001fa00000(0063) knlGS:00000000f75176c0 [ 1.440088] CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 [ 1.440088] CR2: ffff88001da4c018 CR3: 000000001da64000 CR4: 00000000000006f0 [ 1.440088] Stack: [ 1.440088] 0000000000000000 0000000000000000 0000000000000000 0000000000000000 [ 1.440088] 0000000000000066 00000000ffdc3810 000000000a048bd0 000000000a048ca0 [ 1.440088] 0000000000000000 0000000000000066 00000000f775ab70 0000000000000023 [ 1.440088] Call Trace: [ 1.440088] Code: c0 41 52 50 fc 48 83 ec 48 48 89 7c 24 40 48 89 74 24 38 48 89 54 24 30 48 89 4c 24 28 48 89 44 24 20 66 66 90 8b 6d 00 66 66 90 84 24 90 00 00 00 00 40 00 00 0f 85 2f 01 00 00 83 8c 24 8c [ 1.440088] RIP [] ia32_sysenter_target+0x4d/0x5e [ 1.440088] RSP [ 1.440088] CR2: ffff88001da4c018 [ 1.440088] ---[ end trace 7d7a8bfdc14fe3c0 ]--- [ 1.478043] init: console-setup main process (78) killed by KILL signal [ 1.485084] plymouthd (73) used greatest stack depth: 13048 bytes left [ 1.493827] init: plymouth main process (73) killed by KILL signal [ 1.496444] init: plymouth-stop pre-start process (79) terminated with status 2 General error mounting filesystems. A maintenance shell will now be started. CONTROL-D will terminate this shell and reboot the system. [ 1.651076] BUG: unable to handle kernel paging request at ffff88001daa4018 [ 1.653236] IP: [] ia32_sysenter_target+0x4d/0x5e [ 1.654249] PGD 2d6c067 PUD 2d6d067 PMD 1fdf4067 PTE 800000001daa4060 [ 1.654249] Oops: 0000 [#7] SMP DEBUG_PAGEALLOC [ 1.654249] Modules linked in: [ 1.654249] CPU: 0 PID: 83 Comm: bash Tainted: G D 3.17.0-rc7+ #245 [ 1.654249] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_171129-lamiak 04/01/2014 [ 1.654249] task: ffff88001d9f2110 ti: ffff88001daa0000 task.ti: ffff88001daa0000 [ 1.654249] RIP: 0010:[] [] ia32_sysenter_target+0x4d/0x5e [ 1.654249] RSP: 0018:ffff88001daa3f88 EFLAGS: 00010296 [ 1.654249] RAX: 00000000000000af RBX: 0000000000000002 RCX: 000000000812e380 [ 1.654249] RDX: 0000000000000000 RSI: 0000000000000008 RDI: 00000000f773d000 [ 1.654249] RBP: 00000000fffd1da0 R08: ffffffff8138aa0b R09: 0000000000000000 [ 1.654249] R10: 00000000f777bb70 R11: 0000000000000000 R12: 0000000000000000 [ 1.654249] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 1.654249] FS: 0000000000000000(0000) GS:ffff88001fa00000(0063) knlGS:00000000f75966c0 [ 1.654249] CS: 0010 DS: 002b ES: 002b CR0: 000000008005003b [ 1.654249] CR2: ffff88001daa4018 CR3: 000000001da37000 CR4: 00000000000006f0 [ 1.654249] Stack: [ 1.654249] 0000000000000000 0000000000000000 0000000000000000 ffffffff8138aa0b [ 1.654249] 00000000000000af 000000000812e380 0000000000000000 0000000000000008 [ 1.654249] 00000000f773d000 00000000000000af 00000000f777bb70 0000000000000023 [ 1.654249] Call Trace: [ 1.654249] [] ? trace_hardirqs_on_thunk+0x3a/0x3f [ 1.654249] Code: c0 41 52 50 fc 48 83 ec 48 48 89 7c 24 40 48 89 74 24 38 48 89 54 24 30 48 89 4c 24 28 48 89 44 24 20 66 66 90 8b 6d 00 66 66 90 84 24 90 00 00 00 00 40 00 00 0f 85 2f 01 00 00 83 8c 24 8c [ 1.654249] RIP [] ia32_sysenter_target+0x4d/0x5e [ 1.654249] RSP [ 1.654249] CR2: ffff88001daa4018 [ 1.654249] ---[ end trace 7d7a8bfdc14fe3c1 ]--- [ 1.846659] BUG: unable to handle kernel paging request at ffff88001daa4018 [ 1.847580] IP: [] ia32_sysenter_target+0x4d/0x5e [ 1.848331] PGD 2d6c067 PUD 2d6d067 PMD 1fdf4067 PTE 800000001daa4060 [ 1.849222] Oops: 0000 [#8] SMP DEBUG_PAGEALLOC [ 1.849318] Modules linked in: [ 1.849318] CPU: 0 PID: 85 Comm: bash Tainted: G D 3.17.0-rc7+ #245 [ 1.849318] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_171129-lamiak 04/01/2014 [ 1.849318] task: ffff88001d9f2110 ti: ffff88001daa0000 task.ti: ffff88001daa0000 [ 1.849318] RIP: 0010:[] [] ia32_sysenter_target+0x4d/0x5e [ 1.849318] RSP: 0018:ffff88001daa3f88 EFLAGS: 00010296 [ 1.849318] RAX: 00000000000000af RBX: 0000000000000002 RCX: 000000000812e380 [ 1.849318] RDX: 0000000000000000 RSI: 0000000000000008 RDI: 00000000f773d000 [ 1.849318] RBP: 00000000fffd1cf0 R08: ffffffff8138aa0b R09: 0000000000000000 [ 1.849318] R10: 00000000f777bb70 R11: 0000000000000000 R12: 0000000000000000 [ 1.849318] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 1.849318] FS: 0000000000000000(0000) GS:ffff88001fa00000(0063) knlGS:00000000f75966c0 [ 1.849318] CS: 0010 DS: 002b ES: 002b CR0: 000000008005003b [ 1.849318] CR2: ffff88001daa4018 CR3: 000000001da65000 CR4: 00000000000006f0 [ 1.849318] Stack: [ 1.849318] 0000000000000000 0000000000000000 0000000000000000 ffffffff8138aa0b [ 1.849318] 00000000000000af 000000000812e380 0000000000000000 0000000000000008 [ 1.849318] 00000000f773d000 00000000000000af 00000000f777bb70 0000000000000023 [ 1.849318] Call Trace: [ 1.849318] [] ? trace_hardirqs_on_thunk+0x3a/0x3f [ 1.849318] Code: c0 41 52 50 fc 48 83 ec 48 48 89 7c 24 40 48 89 74 24 38 48 89 54 24 30 48 89 4c 24 28 48 89 44 24 20 66 66 90 8b 6d 00 66 66 90 84 24 90 00 00 00 00 40 00 00 0f 85 2f 01 00 00 83 8c 24 8c [ 1.849318] RIP [] ia32_sysenter_target+0x4d/0x5e [ 1.849318] RSP [ 1.849318] CR2: ffff88001daa4018 [ 1.849318] ---[ end trace 7d7a8bfdc14fe3c2 ]--- [ 1.882411] BUG: unable to handle kernel paging request at ffff88001daa8018 [ 1.884212] IP: [] ia32_sysenter_target+0x4d/0x5e [ 1.884506] PGD 2d6c067 PUD 2d6d067 PMD 1fdf4067 PTE 800000001daa8060 [ 1.884506] Oops: 0000 [#9] SMP DEBUG_PAGEALLOC [ 1.884506] Modules linked in: [ 1.884506] CPU: 0 PID: 86 Comm: bash Tainted: G D 3.17.0-rc7+ #245 [ 1.884506] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_171129-lamiak 04/01/2014 [ 1.884506] task: ffff88001da08000 ti: ffff88001daa4000 task.ti: ffff88001daa4000 [ 1.884506] RIP: 0010:[] [] ia32_sysenter_target+0x4d/0x5e [ 1.884506] RSP: 0018:ffff88001daa7f88 EFLAGS: 00010296 [ 1.884506] RAX: 00000000000000af RBX: 0000000000000002 RCX: 000000000812e380 [ 1.884506] RDX: 0000000000000000 RSI: 0000000000000008 RDI: 00000000f773d000 [ 1.884506] RBP: 00000000fffd19e0 R08: ffffffff8138aa0b R09: 0000000000000000 [ 1.884506] R10: 00000000f777bb70 R11: 0000000000000000 R12: 0000000000000000 [ 1.884506] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 1.884506] FS: 0000000000000000(0000) GS:ffff88001fa00000(0063) knlGS:00000000f75966c0 [ 1.884506] CS: 0010 DS: 002b ES: 002b CR0: 000000008005003b [ 1.884506] CR2: ffff88001daa8018 CR3: 000000001da6e000 CR4: 00000000000006f0 [ 1.884506] Stack: [ 1.884506] 0000000000000000 0000000000000000 0000000000000000 ffffffff8138aa0b [ 1.884506] 00000000000000af 000000000812e380 0000000000000000 0000000000000008 [ 1.884506] 00000000f773d000 00000000000000af 00000000f777bb70 0000000000000023 [ 1.884506] Call Trace: [ 1.884506] [] ? trace_hardirqs_on_thunk+0x3a/0x3f [ 1.884506] Code: c0 41 52 50 fc 48 83 ec 48 48 89 7c 24 40 48 89 74 24 38 48 89 54 24 30 48 89 4c 24 28 48 89 44 24 20 66 66 90 8b 6d 00 66 66 90 84 24 90 00 00 00 00 40 00 00 0f 85 2f 01 00 00 83 8c 24 8c [ 1.884506] RIP [] ia32_sysenter_target+0x4d/0x5e [ 1.884506] RSP [ 1.884506] CR2: ffff88001daa8018 [ 1.884506] ---[ end trace 7d7a8bfdc14fe3c3 ]--- root@(none):~# [ 2.388435] Switched to clocksource tsc Qemu version: QEMU emulator version 2.1.0 (Debian 2.1+dfsg-4ubuntu6), Copyright (c) 2003-2008 Fabrice Bellard Invoked as: $QEMU -machine pc,accel=kvm $ARGS -m 512 -net user,restrict=off -net nic,model=virtio -drive file=$QEMUIMAGE,index=0,media=disk,if=virtio -drive file=$QEMUIMAGEB,index=1,media=disk,if=virtio -kernel arch/x86/boot/bzImage -append "ro root=/dev/vda1 $KARGS $*" The guest is a 32-bit Ubuntu 12.10, running the modern kernel of course. Thanks, Rusty.