Hi, I''ve been trying to test out Xen migration, but keep running into a kernel Oops/crash. It might be my setup or I might be running into some other problem, but I''ve searched mailing lists/google and haven''t found anything that has helped. I''m using 3 FC5 boxes all running the latest kernels, updates, etc: One box to export a mounted image file generated with xenguest-install.py via AoE using vblade (have also tried using NFS to export a directory containing the image file). The other 2 boxes are running Xen. The guest starts and runs on either Xen box without a problem, but when trying to do a migration or a live migration between the 2 Xen boxes, in either direction, I run into the kernel crash. The migration actually moves the guest from one box to the other, but it stops responding via the network, and when logging in using ''xm console'' I see a kernel call trace. The guest kinda still works other than networking not working at all, so I tried doing a service network restart, but this causes the guest to totally lock up. If the guest is rebooted it works fine. Bellow is the kernel call trace and what is in the destination Xen server''s xend.log. Thanks Cameron ------------------------- BUG: unable to handle kernel NULL pointer dereference at virtual address 00000000 printing eip: d10c2c27 *pde = ma 00000000 pa fffff000 Oops: 0002 [#1] SMP Modules linked in: ipv6 autofs4 sunrpc xennet ip_conntrack_netbios_ns ipt_REJECT xt_state ip_conntrack nfnetlink xt_tcpudp iptable_filter ip_tables x_tables dm_snapshot dm_zero dm_mirror dm_mod CPU: 0 EIP: 0061:[<d10c2c27>] Not tainted VLI EFLAGS: 00010046 (2.6.17-1.2145_FC5xenU #1) EIP is at backend_changed+0x15c/0x24d [xennet] eax: 00000000 ebx: cf608400 ecx: cf608498 edx: 00000000 esi: 00000001 edi: 00000000 ebp: 00000101 esp: c09cbf70 ds: 007b es: 007b ss: 0069 Process xenwatch (pid: 8, threadinfo=c09ca000 task=c06c6b30) Stack: <0>c09f2200 cf608000 00000000 cf608498 cf608488 c0898dc0 c09ca000 c0898dc0 c051d45e c051cdee c09f2200 00000002 00000002 00000000 c051d5aa c0898dc0 00000000 c06c6b30 c0429cd7 c09cbfbc c09cbfbc c0a43e7c c0429c16 00000000 Call Trace: <c051d45e> xenwatch_thread+0x0/0x163 <c051cdee> xenwatch_handle_callback+0x12/0x45 <c051d5aa> xenwatch_thread+0x14c/0x163 <c0429cd7> autoremove_wake_function+0x0/0x3a <c0429c16> kthread+0xa0/0xcd <c0429b76> kthread+0x0/0xcd <c0402989> kernel_thread_helper+0x5/0xb Code: 08 8b 47 60 01 43 18 ff 43 10 45 81 fd 01 01 00 00 0f 85 35 ff ff ff 8b 44 24 08 89 43 68 8b 53 74 be 01 00 00 00 31 ff 8b 43 68 <89> 02 8b 84 b3 f8 04 00 00 3d ff ff ff bf 76 58 8b 80 98 00 00 EIP: [<d10c2c27>] backend_changed+0x15c/0x24d [xennet] SS:ESP 0069:c09cbf70 <3>BUG: sleeping function called from invalid context at include/linux/rwsem.h:43 in_atomic():0, irqs_disabled():1 <c04242e2> blocking_notifier_call_chain+0x11/0x48 <c04198d6> profile_task_exit+0x10/0x14 <c041b08d> do_exit+0x1b/0x78b <c040571a> die+0x1c0/0x27b <c04057af> die+0x255/0x27b <c040ee98> do_page_fault+0x0/0x70f <c040f4a7> do_page_fault+0x60f/0x70f <c040ee98> do_page_fault+0x0/0x70f <c0404d07> error_code+0x2b/0x30 <d10c2c27> backend_changed+0x15c/0x24d [xennet] <c051d45e> xenwatch_thread+0x0/0x163 <c051cdee> xenwatch_handle_callback+0x12/0x45 <c051d5aa> xenwatch_thread+0x14c/0x163 <c0429cd7> autoremove_wake_function+0x0/0x3a <c0429c16> kthread+0xa0/0xcd <c0429b76> kthread+0x0/0xcd <c0402989> kernel_thread_helper+0x5/0xb BUG: xenwatch/8, lock held at task exit time! [c06083e0] {xenwatch_mutex} .. held by: xenwatch: 8 [c06c6b30, 110] ... acquired at: xenwatch_thread+0x95/0x163 ------------------------ [2006-07-10 12:42:00 xend.XendDomainInfo] DEBUG (XendDomainInfo:260) XendDomainInfo.restore([''domain'', [''domid'', ''5''], [''uuid'', ''08cd716d-1deb-00f4-77b2-66f14244bc16''], [''vcpus'', ''1''], [''vcpu_avail'', ''1''], [''cpu_weight'', ''1.0''], [''memory'', ''256''], [''maxmem'', ''256''], [''bootloader'', ''/usr/bin/pygrub''], [''features''], [''name'', ''xen.guest.migration.test''], [''on_poweroff'', ''destroy''], [''on_reboot'', ''restart''], [''on_crash'', ''restart''], [''image'', [''linux'', [''ramdisk'', ''/var/lib/xen/initrd.ihUbbw''], [''kernel'', ''/var/lib/xen/vmlinuz.4kwzZ2''], [''args'', ''ro root=/dev/VolGroup00/LogVol00'']]], [''device'', [''vif'', [''backend'', ''0''], [''script'', ''vif-bridge''], [''mac'', ''00:16:3e:09:8a:dc'']]], [''device'', [''vbd'', [''backend'', ''0''], [''dev'', ''xvda''], [''uname'', ''phy:etherd/e0.2''], [''mode'', ''w'']]], [''state'', ''-b----''], [''shutdown_reason'', ''poweroff''], [''cpu_time'', ''0.142407299''], [''online_vcpus'', ''1''], [''up_time'', ''508.123579025''], [''start_time'', ''1152498812.32''], [''store_mfn'', ''613739''], [''console_mfn'', ''613738'']]) [2006-07-10 12:42:00 xend.XendDomainInfo] DEBUG (XendDomainInfo:291) parseConfig: config is [''domain'', [''domid'', ''5''], [''uuid'', ''08cd716d-1deb-00f4-77b2-66f14244bc16''], [''vcpus'', ''1''], [''vcpu_avail'', ''1''], [''cpu_weight'', ''1.0''], [''memory'', ''256''], [''maxmem'', ''256''], [''bootloader'', ''/usr/bin/pygrub''], [''features''], [''name'', ''xen.guest.migration.test''], [''on_poweroff'', ''destroy''], [''on_reboot'', ''restart''], [''on_crash'', ''restart''], [''image'', [''linux'', [''ramdisk'', ''/var/lib/xen/initrd.ihUbbw''], [''kernel'', ''/var/lib/xen/vmlinuz.4kwzZ2''], [''args'', ''ro root=/dev/VolGroup00/LogVol00'']]], [''device'', [''vif'', [''backend'', ''0''], [''script'', ''vif-bridge''], [''mac'', ''00:16:3e:09:8a:dc'']]], [''device'', [''vbd'', [''backend'', ''0''], [''dev'', ''xvda''], [''uname'', ''phy:etherd/e0.2''], [''mode'', ''w'']]], [''state'', ''-b----''], [''shutdown_reason'', ''poweroff''], [''cpu_time'', ''0.142407299''], [''online_vcpus'', ''1''], [''up_time'', ''508.123579025''], [''start_time'', ''1152498812.32''], [''store_mfn'', ''613739''], [''console_mfn'', ''613738'']] [2006-07-10 12:42:00 xend.XendDomainInfo] DEBUG (XendDomainInfo:390) parseConfig: result is {''uuid'': ''08cd716d-1deb-00f4-77b2-66f14244bc16'', ''on_crash'': ''restart'', ''on_reboot'': ''restart'', ''image'': [''linux'', [''ramdisk'', ''/var/lib/xen/initrd.ihUbbw''], [''kernel'', ''/var/lib/xen/vmlinuz.4kwzZ2''], [''args'', ''ro root=/dev/VolGroup00/LogVol00'']], ''on_poweroff'': ''destroy'', ''bootloader_args'': None, ''cpus'': None, ''name'': ''xen.guest.migration.test'', ''backend'': [], ''vcpus'': 1, ''cpu_weight'': 1.0, ''features'': None, ''vcpu_avail'': 1, ''memory'': 256, ''device'': [(''vif'', [''vif'', [''backend'', ''0''], [''script'', ''vif-bridge''], [''mac'', ''00:16:3e:09:8a:dc'']]), (''vbd'', [''vbd'', [''backend'', ''0''], [''dev'', ''xvda''], [''uname'', ''phy:etherd/e0.2''], [''mode'', ''w'']])], ''bootloader'': ''/usr/bin/pygrub'', ''cpu'': None, ''maxmem'': 256} [2006-07-10 12:42:00 xend.XendDomainInfo] DEBUG (XendDomainInfo:1216) XendDomainInfo.construct: None [2006-07-10 12:42:00 xend.XendDomainInfo] DEBUG (XendDomainInfo:701) Storing VM details: {''name'': ''xen.guest.migration.test'', ''on_reboot'': ''restart'', ''image'': "(linux (ramdisk /var/lib/xen/initrd.ihUbbw) (kernel /var/lib/xen/vmlinuz.4kwzZ2) (args ''ro root=/dev/VolGroup00/LogVol00''))", ''on_poweroff'': ''destroy'', ''uuid'': ''08cd716d-1deb-00f4-77b2-66f14244bc16'', ''on_crash'': ''restart'', ''vcpus'': ''1'', ''vcpu_avail'': ''1'', ''memory'': ''256'', ''maxmem'': ''256''} [2006-07-10 12:42:00 xend] DEBUG (DevController:110) DevController: writing {''backend-id'': ''0'', ''mac'': ''00:16:3e:09:8a:dc'', ''handle'': ''0'', ''state'': ''1'', ''backend'': ''/local/domain/0/backend/vif/6/0''} to /local/domain/6/device/vif/0. [2006-07-10 12:42:00 xend] DEBUG (DevController:112) DevController: writing {''mac'': ''00:16:3e:09:8a:dc'', ''state'': ''1'', ''handle'': ''0'', ''script'': ''/etc/xen/scripts/vif-bridge'', ''frontend-id'': ''6'', ''domain'': ''xen.guest.migration.test'', ''frontend'': ''/local/domain/6/device/vif/0''} to /local/domain/0/backend/vif/6/0. [2006-07-10 12:42:00 xend] DEBUG (blkif:24) exception looking up device number for xvda: [Errno 2] No such file or directory: ''/dev/xvda'' [2006-07-10 12:42:00 xend] DEBUG (DevController:110) DevController: writing {''virtual-device'': ''51712'', ''backend-id'': ''0'', ''state'': ''1'', ''backend'': ''/local/domain/0/backend/vbd/6/51712''} to /local/domain/6/device/vbd/51712. [2006-07-10 12:42:00 xend] DEBUG (DevController:112) DevController: writing {''domain'': ''xen.guest.migration.test'', ''frontend'': ''/local/domain/6/device/vbd/51712'', ''dev'': ''xvda'', ''state'': ''1'', ''params'': ''etherd/e0.2'', ''mode'': ''w'', ''frontend-id'': ''6'', ''type'': ''phy''} to /local/domain/0/backend/vbd/6/51712. [2006-07-10 12:42:00 xend.XendDomainInfo] DEBUG (XendDomainInfo:736) Storing domain details: {''console/port'': ''2'', ''name'': ''xen.guest.migration.test'', ''console/limit'': ''1048576'', ''vm'': ''/vm/08cd716d-1deb-00f4-77b2-66f14244bc16'', ''domid'': ''6'', ''cpu/0/availability'': ''online'', ''memory/target'': ''262144'', ''store/port'': ''1''} [2006-07-10 12:42:00 xend] DEBUG (balloon:128) Balloon: free 746; need 265; done. [2006-07-10 12:42:00 xend] DEBUG (XendCheckpoint:155) [xc_restore]: /usr/lib/xen/bin/xc_restore 10 15 6 67584 1 2 [2006-07-10 12:42:00 xend] ERROR (XendCheckpoint:234) xc_linux_restore start: max_pfn = 10800 [2006-07-10 12:42:00 xend] ERROR (XendCheckpoint:234) Increased domain reservation by 42000 KB [2006-07-10 12:42:00 xend] ERROR (XendCheckpoint:234) Reloading memory pages: 0% [2006-07-10 12:42:03 xend] ERROR (XendCheckpoint:234) Received all pages (0 races) [2006-07-10 12:42:03 xend] ERROR (XendCheckpoint:2100% [2006-07-10 12:42:03 xend] ERROR (XendCheckpoint:234) Memory reloaded. [2006-07-10 12:42:03 xend] ERROR (XendCheckpoint:234) Decreased reservation by 2101 pages [2006-07-10 12:42:03 xend] ERROR (XendCheckpoint:234) Domain ready to be built. [2006-07-10 12:42:03 xend] ERROR (XendCheckpoint:234) Restore exit with rc=0 [2006-07-10 12:42:03 xend] DEBUG (XendCheckpoint:207) store-mfn 59373 [2006-07-10 12:42:03 xend] DEBUG (XendCheckpoint:207) console-mfn 59372 [2006-07-10 12:42:03 xend.XendDomainInfo] DEBUG (XendDomainInfo:664) XendDomainInfo.completeRestore [2006-07-10 12:42:03 xend.XendDomainInfo] DEBUG (XendDomainInfo:736) Storing domain details: {''console/ring-ref'': ''59372'', ''console/port'': ''2'', ''name'': ''xen.guest.migration.test'', ''console/limit'': ''1048576'', ''vm'': ''/vm/08cd716d-1deb-00f4-77b2-66f14244bc16'', ''domid'': ''6'', ''cpu/0/availability'': ''online'', ''memory/target'': ''262144'', ''store/ring-ref'': ''59373'', ''store/port'': ''1''} [2006-07-10 12:42:03 xend.XendDomainInfo] DEBUG (XendDomainInfo:674) XendDomainInfo.completeRestore done [2006-07-10 12:42:03 xend.XendDomainInfo] DEBUG (XendDomainInfo:919) XendDomainInfo.handleShutdownWatch