Hello,
 
    My server ran about 4days, the kernel crash.
 
/var/log/message:
 
Jan 20 08:05:38 es13 kernel: INFO: task xenwatch:129 blocked for more than 120 seconds.
Jan 20 08:05:38 es13 kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Jan 20 08:05:38 es13 kernel: xenwatch        D ffff8808fea943c0     0   129      2 0x00000000
Jan 20 08:05:38 es13 kernel: ffff8808a6909d18 0000000000000246 ffff8808a6909fd8 00000000000143c0
Jan 20 08:05:38 es13 kernel: ffff8808a6908010 00000000000143c0 00000000000143c0 00000000000143c0
Jan 20 08:05:38 es13 kernel: ffff8808a6909fd8 00000000000143c0 ffff8808a6907540 ffff8808a7720ac0
Jan 20 08:05:38 es13 kernel: Call Trace:
Jan 20 08:05:38 es13 kernel: [<ffffffff815f4339>] schedule+0x29/0x70
Jan 20 08:05:38 es13 kernel: [<ffffffffa04675c5>] xenvif_disconnect+0x85/0xe0 [xen_netback]
Jan 20 08:05:38 es13 kernel: [<ffffffff81082640>] ? wake_up_bit+0x40/0x40
Jan 20 08:05:38 es13 kernel: [<ffffffffa04667d5>] set_backend_state+0xd5/0x1c0 [xen_netback]
Jan 20 08:05:38 es13 kernel: [<ffffffffa0466cc6>] frontend_changed+0xb6/0x100 [xen_netback]
Jan 20 08:05:38 es13 kernel: [<ffffffff813579a8>] xenbus_otherend_changed+0xa8/0xb0
Jan 20 08:05:38 es13 kernel: [<ffffffff81357be0>] frontend_changed+0x10/0x20
Jan 20 08:05:38 es13 kernel: [<ffffffff81355731>] xenwatch_thread+0xb1/0x170
Jan 20 08:05:38 es13 kernel: [<ffffffff81082640>] ? wake_up_bit+0x40/0x40
Jan 20 08:05:38 es13 kernel: [<ffffffff81355680>] ? xs_watch+0x60/0x60
Jan 20 08:05:38 es13 kernel: [<ffffffff81081e2e>] kthread+0xce/0xe0
Jan 20 08:05:38 es13 kernel: [<ffffffff8100392e>] ? xen_end_context_switch+0x1e/0x30
Jan 20 08:05:38 es13 kernel: [<ffffffff81081d60>] ? kthread_freezable_should_stop+0x70/0x70
Jan 20 08:05:38 es13 kernel: [<ffffffff815fe66c>] ret_from_fork+0x7c/0xb0
Jan 20 08:05:38 es13 kernel: [<ffffffff81081d60>] ? kthread_freezable_should_stop+0x70/0x70
 
# xl list
Name                                        ID   Mem VCPUs   State  Time(s)
Domain-0                                     0 34899    24     r-----  1847934.0
(null)                                    2752     0     1     --p--d      43.7
(null)                                    2754     0     1     --p--d     168.2
(null)                                    2755     0     1     --p--d     153.1
(null)                                    2756     0     1     --p--d      32.8
(null)                                    2757     0     1     --p--d     234.9
(null)                                    2758     0     1     --p--d      52.1
(null)                                    2759     0     1     --p--d      24.3
(null)                                    2760     0     1     --p--d      20.5
(null)                                    2761     0     1     --p--d     261.9
(null)                                    2762     0     1     --p--d      91.0
(null)                                    2763     0     1     --p--d      26.6
(null)                                    2764     0     1     --p--d      26.2
(null)                                    2765     0     1     --p--d      56.5
(null)                                    2766     0     1     --p--d      10.6
(null)                                    2767     0     1     --p--d      32.7
(null)                                    2768     0     1     --p--d      42.1
(null)                                    2769     0     1     --p--d      65.2
(null)                                    2770     0     1     --p--d     274.8
(null)                                    2771     0     1     --p--d     107.2
(null)                                    2772     0     1     --p--d      32.7
 
# xl info
release                : 3.10.20-11.el6.centos.alt.x86_64
version                : #1 SMP Sat Nov 23 23:08:56 UTC 2013
machine                : x86_64
nr_cpus                : 24
max_cpu_id             : 23
nr_nodes               : 2
cores_per_socket       : 6
threads_per_core       : 2
cpu_mhz                : 2600
hw_caps                : b7ebfbff:77bee3ff:2c100800:00000001:00000001:00000281:00000000:00000100
virt_caps              : hvm hvm_directio
total_memory           : 65506
free_memory            : 6667
sharing_freed_memory   : 0
sharing_used_memory    : 0
outstanding_claims     : 0
free_cpus              : 0
xen_major              : 4
xen_minor              : 8
xen_extra              : .0
xen_version            : 4.8.0
xen_caps               : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64
xen_scheduler          : credit
xen_pagesize           : 4096
platform_params        : virt_start=0xffff800000000000
xen_changeset          :
xen_commandline        : dom0_mem=35736884 loglvl=all guest_loglvl=all
cc_compiler            : gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-16)
cc_compile_by          : xikangjie
cc_compile_domain      : (none)
cc_compile_date        : Fri Dec  9 14:49:01 CST 2016
build_id               : 8bd07d490bbae9862d3bfdca07c7551e8792389f
xend_config_format     : 4
 
And I can’t create new vms.
 
Xen version is 4.8.0, Linux kernel version is 3.10.20-11, does I need to upgrade linux kernel?
 
- xikangjie