Just tried with the updated kernel 2.6.24-18-xen and still have the same issues with a crash at netfront.c:855. Centos 5.1 Dom0 running xen-3.0.3-41.el5_1.5 Full boot and crash output below [ 0.000000] Linux version 2.6.24-18-xen (buildd@terranova) (gcc version 4.2.3 (Ubuntu 4.2.3-2ubuntu7)) #1 SMP Thu May 29 00:39:30 UTC 2008 (Ubuntu 2.6.24-4.6-generic) [ 0.000000] Reserving virtual address space above 0xf5800000 [ 0.000000] BIOS-provided physical RAM map: [ 0.000000] Xen: 0000000000000000 - 0000000009e00000 (usable) [ 0.000000] 0MB HIGHMEM available. [ 0.000000] 158MB LOWMEM available. [1226229.780011] Zone PFN ranges: [1226229.780014] DMA 0 -> 4096 [1226229.780018] Normal 4096 -> 40448 [1226229.780020] HighMem 40448 -> 40448 [1226229.780022] Movable zone start PFN for each node [1226229.780025] early_node_map[1] active PFN ranges [1226229.780027] 0: 0 -> 40448 [1226229.788921] ACPI in unprivileged domain disabled [1226229.788940] Allocating PCI resources starting at 10000000 (gap: 09e00000:f6200000) [1226229.789057] Built 1 zonelists in Zone order, mobility grouping on. Total pages: 40132 [1226229.789065] Kernel command line: root=/dev/sda2 ro root=UUID=87fea4c2-db1f-4743-bab0-da95e5c8e594 ro xencons=tty single [1226229.789400] Enabling fast FPU save and restore... done. [1226229.789409] Enabling unmasked SIMD FPU exception support... done. [1226229.789414] Initializing CPU#0 [1226229.789643] PID hash table entries: 1024 (order: 10, 4096 bytes) [1226229.789689] Xen reported: 1665.028 MHz processor. [ 0.104278] console [tty0] enabled [ 0.104498] Console: colour dummy device 80x25 [ 0.104715] Dentry cache hash table entries: 32768 (order: 5, 131072 bytes) [ 0.104996] Inode-cache hash table entries: 16384 (order: 4, 65536 bytes) [ 0.105077] Software IO TLB disabled [ 0.105087] vmalloc area: ca800000-f53fe000, maxmem 2d800000 [ 0.110360] Memory: 129472k/161792k available (2225k kernel code, 23988k reserved, 1010k data, 212k init, 0k highmem) [ 0.110400] virtual kernel memory layout: [ 0.110401] fixmap : 0xf568d000 - 0xf57ff000 (1480 kB) [ 0.110403] pkmap : 0xf5400000 - 0xf5600000 (2048 kB) [ 0.110405] vmalloc : 0xca800000 - 0xf53fe000 ( 683 MB) [ 0.110406] lowmem : 0xc0000000 - 0xc9e00000 ( 158 MB) [ 0.110408] .init : 0xc042f000 - 0xc0464000 ( 212 kB) [ 0.110409] .data : 0xc032c481 - 0xc0428d04 (1010 kB) [ 0.110411] .text : 0xc0100000 - 0xc032c481 (2225 kB) [ 0.110424] Checking if this processor honours the WP bit even in supervisor mode... Ok. [ 0.177796] Calibrating delay using timer specific routine.. 3332.30 BogoMIPS (lpj=6664617) [ 0.177933] Security Framework initialized [ 0.177945] SELinux: Disabled at boot. [ 0.177958] AppArmor: AppArmor initialized [ 0.177966] Failure registering capabilities with primary security module. [ 0.177998] Mount-cache hash table entries: 512 [ 0.178248] CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line) [ 0.178253] CPU: L2 Cache: 256K (64 bytes/line) [ 0.178273] Compat vDSO mapped to f57fe000. [ 0.178287] Checking 'hlt' instruction... OK. [ 0.178638] SMP alternatives: switching to UP code [ 0.179295] Freeing SMP alternatives: 11k freed [ 0.179489] Early unpacking initramfs... done [ 0.246524] Brought up 1 CPUs [ 0.247612] net_namespace: 64 bytes [ 0.247626] failed to set up cpufreq notifier [ 0.265400] Time: 165:165:165 Date: 165/165/65 [ 0.265470] NET: Registered protocol family 16 [ 0.266595] Brought up 1 CPUs [ 0.266619] PCI: Fatal: No config space access function found [ 0.266624] PCI: setting up Xen PCI frontend stub [ 0.267685] ACPI: Interpreter disabled. [ 0.267697] Linux Plug and Play Support v0.97 (c) Adam Belay [ 0.267750] pnp: PnP ACPI: disabled [ 0.267895] xen_mem: Initialising balloon driver. [ 0.268793] Setting mem allocation to 153600 kiB [ 0.269308] PCI: System does not support PCI [ 0.269314] PCI: System does not support PCI [ 0.270892] NET: Registered protocol family 8 [ 0.270898] NET: Registered protocol family 20 [ 0.271038] AppArmor: AppArmor Filesystem Enabled [ 0.271732] NET: Registered protocol family 2 [ 0.274773] Time: xen clocksource has been installed. [ 0.306875] IP route cache hash table entries: 2048 (order: 1, 8192 bytes) [ 0.307219] TCP established hash table entries: 8192 (order: 4, 65536 bytes) [ 0.307358] TCP bind hash table entries: 8192 (order: 4, 65536 bytes) [ 0.307492] TCP: Hash tables configured (established 8192 bind 8192) [ 0.307498] TCP reno registered [ 0.318967] checking if image is initramfs... it is [ 0.423381] Freeing initrd memory: 17836k freed [ 0.424296] audit: initializing netlink socket (disabled) [ 0.424351] audit(1212547892.753:1): initialized [ 0.424705] VFS: Disk quotas dquot_6.5.1 [ 0.424773] Dquot-cache hash table entries: 1024 (order 0, 4096 bytes) [ 0.424953] io scheduler noop registered [ 0.424969] io scheduler anticipatory registered [ 0.424984] io scheduler deadline registered [ 0.425021] io scheduler cfq registered (default) [ 0.428459] Xen virtual console successfully installed as tty1 [ 0.428663] Event-channel device installed. [ 0.448529] Successfully initialized TPM backend driver. [ 0.450635] xen-vbd: registered block device major 8 [ 0.451027] netfront: Initialising virtual ethernet driver. [ 0.514992] rtc: IRQ 8 is not free. [ 0.516289] RAMDISK driver initialized: 16 RAM disks of 65536K size 1024 blocksize [ 0.516539] input: Macintosh mouse button emulation as /devices/virtual/input/input0 [ 0.516864] PNP: No PS/2 controller found. Probing ports directly. [ 0.517737] i8042.c: No controller found. [ 0.520869] mice: PS/2 mouse device common for all mice [ 0.520949] cpuidle: using governor ladder [ 0.521085] NET: Registered protocol family 1 [ 0.521134] Using IPI No-Shortcut mode [ 0.521184] registered taskstats version 1 [ 0.524213] ------------[ cut here ]------------ [ 0.524229] kernel BUG at /build/buildd/linux-2.6.24/debian/build/custom-source-xen/drivers/xen/netfront/netfront.c:855! [ 0.524237] invalid opcode: 0000 [#1] SMP [ 0.524243] Modules linked in: [ 0.524247] [ 0.524252] Pid: 18, comm: xenwatch Not tainted (2.6.24-18-xen #1) [ 0.524257] EIP: 0061:[] EFLAGS: 00010002 CPU: 0 [ 0.524270] EIP is at network_alloc_rx_buffers+0x503/0x510 [ 0.524275] EAX: 00000040 EBX: c90219b4 ECX: 00000041 EDX: 0000003f [ 0.524280] ESI: 00007783 EDI: c9020480 EBP: 0000023f ESP: c7ed1edc [ 0.524285] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: e021 [ 0.524290] Process xenwatch (pid: 18, ti=c7ed0000 task=c7ecabd0 task.ti=c7ed0000) [ 0.524294] Stack: ffffffff c902119c c9020000 000007e0 00000100 003f2ce0 00000040 00000000 [ 0.524308] c7783000 00000040 c9020550 c75eb000 00000040 0000003f c90215b4 00000040 [ 0.524320] 00000000 00000000 00007ff0 00000000 c9020480 00000000 00000100 c026a8ba [ 0.524332] Call Trace: [ 0.524337] [] backend_changed+0x76a/0x8c0 [ 0.524346] [] otherend_changed+0x8f/0xa0 [ 0.524353] [] xenwatch_thread+0x0/0x140 [ 0.524365] [] xenwatch_handle_callback+0x1a/0x60 [ 0.524372] [] xenwatch_thread+0x12a/0x140 [ 0.524379] [] xenwatch_handle_callback+0x0/0x60 [ 0.524386] [] autoremove_wake_function+0x0/0x40 [ 0.524398] [] kthread+0x42/0x70 [ 0.524404] [] kthread+0x0/0x70 [ 0.524410] [] kernel_thread_helper+0x7/0x10 [ 0.524419] ======================= [ 0.524422] Code: 00 00 8b 54 24 30 39 d0 74 06 eb 8c 85 c0 75 1b 83 ea 01 83 fa ff 66 90 75 f2 8b 54 24 30 e9 11 ff ff ff 0f 0b eb fe 0f 0b eb fe <0f> 0b eb fe 0f 0b eb fe 90 8d 74 26 00 83 ec 20 85 d2 89 5c 24 [ 0.524484] EIP: [] network_alloc_rx_buffers+0x503/0x510 SS:ESP e021:c7ed1edc [ 0.524496] Kernel panic - not sync