I'm running qemu on a 4.8.x host which is also running under KVM (openstack, probably ubuntu) on a server that i don't control. I've had issues with this also on 4.7 and on a different physical host. In guest i see this: Nov 30 14:09:50 foobar qemu-kvm-guest[59]: [21618.540365] BUG: unable to handle kernel paging request at 0000000008473000 Nov 30 14:09:50 foobar qemu-kvm-guest[59]: [21618.550075] IP: [<ffffffff810a44bf>] search_module_extables+0x2f/0x70 Nov 30 14:09:50 foobar qemu-kvm-guest[59]: [21618.550075] PGD 0 Nov 30 14:09:50 foobar qemu-kvm-guest[59]: [21618.550075] Oops: 0000 [#1] Nov 30 14:09:50 foobar qemu-kvm-guest[59]: [21618.550075] Modules linked in: 9p fscache af_packet nft_limit nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nf_log_ipv6 nf_log_ipv4 nf_log_common nft_counter nft_l Nov 30 14:09:50 foobar qemu-kvm-guest[59]: [21618.550075] CPU: 0 PID: 398 Comm: systemd-network Tainted: G W 4.8.9-1-kvmnogr #1 Nov 30 14:09:50 foobar qemu-kvm-guest[59]: [21618.550075] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.1-20161122_114906-anatol 04/01/2014 Nov 30 14:09:50 foobar qemu-kvm-guest[59]: [21618.550075] task: ffff8bce7f426e00 task.stack: ffff8bce7b0d4000 Nov 30 14:09:51 foobar qemu-kvm-guest[59]: [21618.550075] RIP: 0010:[<ffffffff810a44bf>] [<ffffffff810a44bf>] search_module_extables+0x2f/0x70 Nov 30 14:09:51 foobar qemu-kvm-guest[59]: [21618.550075] RSP: 0000:ffff8bce7b0d78a8 EFLAGS: 00010202 Nov 30 14:09:51 foobar qemu-kvm-guest[59]: [21618.550075] RAX: ffffffffc0265348 RBX: ffffffffc0265340 RCX: ffffffff810ddb97 Nov 30 14:09:51 foobar qemu-kvm-guest[59]: [21618.550075] RDX: ffffffff810a44bf RSI: ffffffff814a4110 RDI: ffffffff810a44bf Nov 30 14:09:51 foobar qemu-kvm-guest[59]: [21618.550075] RBP: ffff8bce7b0d78b8 R08: aaaaaaaaaaaaaaab R09: 0000000000000000 Nov 30 14:09:51 foobar qemu-kvm-guest[59]: [21618.550075] R10: 0000000000000046 R11: 0000000000000001 R12: ffffffff810a44bf Nov 30 14:09:51 foobar qemu-kvm-guest[59]: [21618.550075] R13: 0000000000000000 R14: 000000000000000b R15: ffff8bce7f426e00 Nov 30 14:09:51 foobar qemu-kvm-guest[59]: [21618.550075] FS: 00007f024d2367c0(0000) GS:ffffffff8181f000(0000) knlGS:0000000000000000 Nov 30 14:09:51 foobar qemu-kvm-guest[59]: [21618.550075] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 Nov 30 14:09:51 foobar qemu-kvm-guest[59]: [21618.550075] CR2: 0000000008473000 CR3: 0000000039210000 CR4: 00000000001406b0 Nov 30 14:09:51 foobar qemu-kvm-guest[59]: [21618.550075] Stack: Nov 30 14:09:51 foobar qemu-kvm-guest[59]: [21618.550075] ffffffff810a44bf 000000000000000e ffff8bce7b0d78d0 ffffffff81070041 Nov 30 14:09:51 foobar qemu-kvm-guest[59]: [21618.550075] ffff8bce7b0d7a78 ffff8bce7b0d78f0 ffffffff8102a4e9 0000000000000000 Nov 30 14:09:51 foobar qemu-kvm-guest[59]: [21618.550075] ffff8bce7b0d7a78 ffff8bce7b0d7958 ffffffff810291b3 ffff8bce7fa84000 Nov 30 14:09:51 foobar qemu-kvm-guest[59]: [21618.550075] Call Trace: Nov 30 14:09:51 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff810a44bf>] ? search_module_extables+0x2f/0x70 Nov 30 14:09:51 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff81070041>] search_exception_tables+0x31/0x40 Nov 30 14:09:52 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff8102a4e9>] fixup_exception+0x19/0x40 Nov 30 14:09:52 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff810291b3>] no_context+0x43/0x310 Nov 30 14:09:52 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff8102955a>] __bad_area_nosemaphore+0xda/0x1c0 Nov 30 14:09:52 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff810296a0>] bad_area+0x40/0x50 Nov 30 14:09:52 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff81029bd5>] __do_page_fault+0x335/0x3e0 Nov 30 14:09:52 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff81029cd2>] do_page_fault+0x22/0x30 Nov 30 14:09:52 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff811830f0>] ? cn_esc_printf+0x110/0x110 Nov 30 14:09:52 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff81025a43>] do_async_page_fault+0x13/0x60 Nov 30 14:09:52 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff814a2998>] async_page_fault+0x28/0x30 Nov 30 14:09:52 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff811830f0>] ? cn_esc_printf+0x110/0x110 Nov 30 14:09:52 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff81253dda>] ? copy_user_generic_unrolled+0x1a/0xc0 Nov 30 14:09:52 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff811830f0>] ? cn_esc_printf+0x110/0x110 Nov 30 14:09:52 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff811830f0>] ? cn_esc_printf+0x110/0x110 Nov 30 14:09:52 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff810a44bf>] ? search_module_extables+0x2f/0x70 Nov 30 14:09:52 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff811830f0>] ? cn_esc_printf+0x110/0x110 Nov 30 14:09:52 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff81070041>] search_exception_tables+0x31/0x40 Nov 30 14:09:52 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff8102a4e9>] fixup_exception+0x19/0x40 Nov 30 14:09:52 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff810291b3>] no_context+0x43/0x310 Nov 30 14:09:52 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff811251b0>] ? alloc_debug_processing+0x70/0x1b0 Nov 30 14:09:52 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff8102955a>] __bad_area_nosemaphore+0xda/0x1c0 Nov 30 14:09:52 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff8113568f>] ? __check_object_size+0x4f/0x383 Nov 30 14:09:53 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff810296a0>] bad_area+0x40/0x50 Nov 30 14:09:53 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff81029bd5>] __do_page_fault+0x335/0x3e0 Nov 30 14:09:53 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff81029cd2>] do_page_fault+0x22/0x30 Nov 30 14:09:53 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff81025a43>] do_async_page_fault+0x13/0x60 Nov 30 14:09:53 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff814a2998>] async_page_fault+0x28/0x30 Nov 30 14:09:53 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff811830f0>] ? cn_esc_printf+0x110/0x110 Nov 30 14:09:53 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff810645cf>] ? get_signal+0x17f/0x4a0 Nov 30 14:09:53 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff8100dcd2>] do_signal+0x32/0x5a0 Nov 30 14:09:53 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff811045cb>] ? print_vma_addr+0x7b/0x100 Nov 30 14:09:53 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff8102953e>] ? __bad_area_nosemaphore+0xbe/0x1c0 Nov 30 14:09:53 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff81084e9a>] ? vprintk_default+0x1a/0x20 Nov 30 14:09:53 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff810296a0>] ? bad_area+0x40/0x50 Nov 30 14:09:53 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff81029bd5>] ? __do_page_fault+0x335/0x3e0 Nov 30 14:09:53 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff81001052>] exit_to_usermode_loop+0x82/0xa0 Nov 30 14:09:53 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff810011b8>] prepare_exit_to_usermode+0x18/0x20 Nov 30 14:09:53 foobar qemu-kvm-guest[59]: [21618.550075] [<ffffffff814a20e2>] retint_user+0x8/0x10 Nov 30 14:09:54 foobar qemu-kvm-guest[59]: [21618.550075] Code: d3 78 00 48 3d 10 18 83 81 74 58 55 48 89 e5 41 54 49 89 fc 53 48 8d 58 f8 eb 10 48 8b 43 08 48 3d 10 18 83 81 48 8d 58 f8 74 31 <83> 3b 03 74 eb 8b 83 3c 0 Nov 30 14:09:54 foobar qemu-kvm-guest[59]: [21618.550075] RIP [<ffffffff810a44bf>] search_module_extables+0x2f/0x70 Nov 30 14:09:54 foobar qemu-kvm-guest[59]: [21618.550075] RSP <ffff8bce7b0d78a8> Nov 30 14:09:54 foobar qemu-kvm-guest[59]: [21618.550075] CR2: 0000000008473000 Nov 30 14:09:54 foobar qemu-kvm-guest[59]: [21623.232115] ---[ end trace 73878b0600d58483 ]--- Nov 30 14:09:54 foobar qemu-kvm-guest[59]: [21623.266619] Kernel panic - not syncing: Fatal exception Nov 30 14:09:54 foobar qemu-kvm-guest[59]: [21623.276559] Kernel Offset: 0x0 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) and on the host Nov 30 14:11:55 host.example.org kernel: INFO: task dnsmasq:538 blocked for more than 120 seconds. Nov 30 14:11:55 host.example.org kernel: Not tainted 4.8.9-1-kvmnogr #1 Nov 30 14:11:55 host.example.org kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Nov 30 14:11:55 host.example.org kernel: dnsmasq D ffff9945b437fe98 0 538 413 0x00000180 Nov 30 14:11:55 host.example.org kernel: ffff9945b437fe98 ffff9945b5814200 0000000000000000 ffff9945b4380000 Nov 30 14:11:55 host.example.org kernel: ffff9945b437fef0 00000000ffffffff 00007ffe0839d2c0 00007fd9c36a1c00 Nov 30 14:11:55 host.example.org kernel: ffff9945b437feb0 ffffffff8a49ec7e 00000000000000ed ffff9945b437ff38 Nov 30 14:11:55 host.example.org kernel: Call Trace: Nov 30 14:11:55 host.example.org kernel: [<ffffffff8a49ec7e>] schedule+0x2e/0x80 Nov 30 14:11:55 host.example.org kernel: [<ffffffff8a0258ac>] kvm_async_pf_task_wait+0x17c/0x1c0 Nov 30 14:11:55 host.example.org kernel: [<ffffffff8a025a87>] do_async_page_fault+0x57/0x60 Nov 30 14:11:55 host.example.org kernel: [<ffffffff8a4a2998>] async_page_fault+0x28/0x30 I suppose my question is if this could have something to do with the kernel itself rather than with the hoster doing weird things and if this is worth debugging or not..and what can I do to provide more information. Note that I can't reproduce this at will..it takes some time and appears somewhat random -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
