由XCP驱动的我们的一个生产集群突然没有反应。 重新启动和一些调查后，我们在dom0机器syslog中发现这样的日志：
Oct 26 20:32:03 hetzner-2-mrx kernel: [1797931.659040] irq 339: nobody cared (try booting with the "irqpoll" option) Oct 26 20:32:03 hetzner-2-mrx kernel: [1797931.659058] Pid: 0, comm: swapper/3 Tainted: GCO 3.2.0-24-generic #37-Ubuntu Oct 26 20:32:03 hetzner-2-mrx kernel: [1797931.659060] Call Trace: Oct 26 20:32:03 hetzner-2-mrx kernel: [1797931.659062] <IRQ> [<ffffffff810db37d>] __report_bad_irq+0x3d/0xe0 Oct 26 20:32:03 hetzner-2-mrx kernel: [1797931.659071] [<ffffffff810db605>] note_interrupt+0x135/0x190 Oct 26 20:32:03 hetzner-2-mrx kernel: [1797931.659074] [<ffffffff810d8e69>] handle_irq_event_percpu+0xa9/0x220 Oct 26 20:32:03 hetzner-2-mrx kernel: [1797931.659078] [<ffffffff8130ff3b>] ? radix_tree_lookup+0xb/0x10 Oct 26 20:32:03 hetzner-2-mrx kernel: [1797931.659081] [<ffffffff810d9031>] handle_irq_event+0x51/0x80 Oct 26 20:32:03 hetzner-2-mrx kernel: [1797931.659084] [<ffffffff810dc187>] handle_edge_irq+0x87/0x140 Oct 26 20:32:03 hetzner-2-mrx kernel: [1797931.659089] [<ffffffff813a8829>] __xen_evtchn_do_upcall+0x199/0x250 Oct 26 20:32:03 hetzner-2-mrx kernel: [1797931.659092] [<ffffffff813aa96f>] xen_evtchn_do_upcall+0x2f/0x50 Oct 26 20:32:03 hetzner-2-mrx kernel: [1797931.659096] [<ffffffff81666d3e>] xen_do_hypervisor_callback+0x1e/0x30 Oct 26 20:32:03 hetzner-2-mrx kernel: [1797931.659097] <EOI> [<ffffffff810013aa>] ? hypercall_page+0x3aa/0x1000 Oct 26 20:32:03 hetzner-2-mrx kernel: [1797931.659104] [<ffffffff810013aa>] ? hypercall_page+0x3aa/0x1000 Oct 26 20:32:03 hetzner-2-mrx kernel: [1797931.659107] [<ffffffff8100a1d0>] ? xen_safe_halt+0x10/0x20 Oct 26 20:32:03 hetzner-2-mrx kernel: [1797931.659110] [<fff cat / proc / interrupts中的IRQ 339：
339: ... xen-pirq-msi-x eth0
eth0是硬件网卡。
虽然主机似乎挂起，来宾机器继续工作，所以我们对其中一个虚拟主机的小型内部监控logging如下：
[2012-10-26 20:31:51] [OK......] 200 OK : 113159149 ns [2012-10-26 20:32:40] [DISASTER] 500 Can't connect to [hostname]:80 (No route to host) : 47763284432 ns ... [2012-10-26 20:34:40] [DISASTER] 500 Can't connect to [hostname]:80 (No route to host) : 46894835070 ns [2012-10-26 20:34:57] [DISASTER] 500 Can't connect to [hostname]:80 (Bad hostname) : 16821741955 ns ... [2012-10-26 20:38:18] [DISASTER] 500 Can't connect to [hostname]:80 (Bad hostname) : 20103298289 ns [2012-10-26 20:38:37] [DISASTER] 500 Can't connect to [hostname]:80 (Bad hostname) : 17895754943 ns
主机和客户操作系统：Ubuntu 12.04 LTS，
05:00.0 Ethernet controller: Intel Corporation 82574L Gigabit Network Connection Subsystem: ASUSTeK Computer Inc. Device 8369 Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+ Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx+ Latency: 0, Cache Line Size: 64 bytes Interrupt: pin A routed to IRQ 17 Region 0: Memory at fe500000 (32-bit, non-prefetchable) [size=128K] Region 2: I/O ports at e000 [size=32] Region 3: Memory at fe520000 (32-bit, non-prefetchable) [size=16K] Capabilities: <access denied> Kernel driver in use: e1000e Kernel modules: e1000e
任何提示如何debugging呢？