[Xen-users] Xen unprivileged domain crash. Bug in Xen ?

[Jasper Siepkes <jsiepkes@xxxxxxxxx>]

Hi,

I experienced a crash today with Xen 3.0.1 running on Debian Sarge with a
unprivileged domain (Also running Sarge). Xen automatically rebooted the
domain. This is what I pulled from the Xen logs:

-----------------8<----------------------------------
[2006-07-14 16:32:47 xend.XendDomainInfo] WARNING (XendDomainInfo:806)
Domain has crashed: name=domu2 id=16.
[2006-07-14 16:32:47 xend.XendDomainInfo] DEBUG (XendDomainInfo:1317)
XendDomainInfo.destroyDomain(16)
[2006-07-14 16:32:48 xend.XendDomainInfo] DEBUG (XendDomainInfo:177)
XendDomainInfo.create(['domain', ['domid', 16], ['uuid',
'6e49df9a-664f-3b58-d88b-a7297acbf0f1'], ['ssidref', 0], ['vcpus', 1],
['vcpu_avail', 1], ['cpu_weight', 1.0], ['memory', 1024], ['maxmem', 1024],
['name', 'domu2'], ['on_poweroff', 'destroy'], ['on_reboot', 'restart'],
['on_crash', 'restart'], ['image', ['linux', ['kernel',
'/boot/xen-linux-2.6.12.6-xenu'], ['root', '/dev/hda1 rw'], ['args', '4']]],
['device', ['vif', ['backend', 0], ['script', 'vif-bridge'], ['bridge',
'xenbr0'], ['mac', '00:16:3e:70:01:01']]], ['device', ['vif', ['backend',
0], ['script', 'vif-bridge'], ['bridge', 'xenbr1'], ['mac',
'00:16:3e:70:02:01']]], ['device', ['vbd', ['backend', 0], ['dev', 'hda1'],
['uname', 'phy:VG1/domu2-root'], ['mode', 'w']]], ['device', ['vbd',
['backend', 0], ['dev', 'hda2'], ['uname', 'phy:VG1/domu2-swap'], ['mode',
'w']]], ['device', ['vbd', ['backend', 0], ['dev', 'hda3'], ['uname',
'phy:VG1/oracle-udmp1'], ['mode', 'w']]], ['device', ['vbd', ['backend', 0],
['dev', 'hda4'], ['uname', 'phy:VG1/oracle-udmp2'], ['mode', 'w']]],
['state', '----c-'], ['shutdown_reason', 'crash'], ['cpu_time',
8662.2658150719999], ['online_vcpus', 1], ['up_time', '258371.445099'],
['start_time', '1152629196.27'], ['store_mfn', 635772], ['console_mfn',
635771]])
[2006-07-14 16:32:48 xend.XendDomainInfo] DEBUG (XendDomainInfo:282)
parseConfig: config is ['domain', ['domid', 16], ['uuid',
'6e49df9a-664f-3b58-d88b-a7297acbf0f1'], ['ssidref', 0], ['vcpus', 1],
['vcpu_avail', 1], ['cpu_weight', 1.0], ['memory', 1024], ['maxmem', 1024],
['name', 'domu2'], ['on_poweroff', 'destroy'], ['on_reboot', 'restart'],
['on_crash', 'restart'], ['image', ['linux', ['kernel',
'/boot/xen-linux-2.6.12.6-xenu'], ['root', '/dev/hda1 rw'], ['args', '4']]],
['device', ['vif', ['backend', 0], ['script', 'vif-bridge'], ['bridge',
'xenbr0'], ['mac', '00:16:3e:70:01:01']]], ['device', ['vif', ['backend',
0], ['script', 'vif-bridge'], ['bridge', 'xenbr1'], ['mac',
'00:16:3e:70:02:01']]], ['device', ['vbd', ['backend', 0], ['dev', 'hda1'],
['uname', 'phy:VG1/domu2-root'], ['mode', 'w']]], ['device', ['vbd',
['backend', 0], ['dev', 'hda2'], ['uname', 'phy:VG1/domu2-swap'], ['mode',
'w']]], ['device', ['vbd', ['backend', 0], ['dev', 'hda3'], ['uname',
'phy:VG1/oracle-udmp1'], ['mode', 'w']]], ['device', ['vbd', ['backend', 0],
['dev', 'hda4'], ['uname', 'phy:VG1/oracle-udmp2'], ['mode', 'w']]],
['state', '----c-'], ['shutdown_reason', 'crash'], ['cpu_time',
8662.2658150719999], ['online_vcpus', 1], ['up_time', '258371.445099'],
['start_time', '1152629196.27'], ['store_mfn', 635772], ['console_mfn',
635771]]
[2006-07-14 16:32:48 xend.XendDomainInfo] DEBUG (XendDomainInfo:376)
parseConfig: result is {'ssidref': 0, 'uuid':
'6e49df9a-664f-3b58-d88b-a7297acbf0f1', 'on_crash': 'restart', 'on_reboot':
'restart', 'image': ['linux', ['kernel', '/boot/xen-linux-2.6.12.6-xenu'],
['root', '/dev/hda1 rw'], ['args', '4']], 'on_poweroff': 'destroy', 'cpus':
None, 'name': 'domu2', 'backend': [], 'vcpus': 1, 'cpu_weight': 1.0,
'vcpu_avail': 1, 'memory': 1024, 'device': [('vif', ['vif', ['backend', 0],
['script', 'vif-bridge'], ['bridge', 'xenbr0'], ['mac',
'00:16:3e:70:01:01']]), ('vif', ['vif', ['backend', 0], ['script',
'vif-bridge'], ['bridge', 'xenbr1'], ['mac', '00:16:3e:70:02:01']]), ('vbd',
['vbd', ['backend', 0], ['dev', 'hda1'], ['uname', 'phy:VG1/domu2-root'],
['mode', 'w']]), ('vbd', ['vbd', ['backend', 0], ['dev', 'hda2'], ['uname',
'phy:VG1/domu2-swap'], ['mode', 'w']]), ('vbd', ['vbd', ['backend', 0],
['dev', 'hda3'], ['uname', 'phy:VG1/oracle-udmp1'], ['mode', 'w']]), ('vbd',
['vbd', ['backend', 0], ['dev', 'hda4'], ['uname', 'phy:VG1/oracle-udmp2'],
['mode', 'w']])], 'bootloader': None, 'cpu': None, 'maxmem': 1024}
-----------------8<----------------------------------

This log comes from inside the domain:

-----------------8<----------------------------------
Jul 14 16:26:28 domu2 kernel: network_tx_buf_gc: warning -- grant still in
use by backend domain.
Jul 14 16:27:06 domu2 last message repeated 24 times
Jul 14 16:27:06 domu2 last message repeated 98 times
Jul 14 16:30:16 domu2 kernel: network_tx_buf_gc: warning -- grant still in
use by backend domain.
Jul 14 16:30:44 domu2 last message repeated 124 times
Jul 14 16:32:33 domu2 kernel: network_tx_buf_gc: warning -- grant still in
use by backend domain.
Jul 14 16:33:10 domu2 kernel: klogd 1.4.1#17, log source = /proc/kmsg
started.
Jul 14 16:33:10 domu2 kernel: Cannot find map file.
-----------------8<----------------------------------

Although I don't have concrete proof, it seems that the crash is caused by
the "network_tx_buf_gc: warning -- grant still in use by backend domain."
Warning. I searched around quite a bit but couldn't find any hint on what
this error means. Does it mean the Virtual Ethernet Interface is being
overloaded ? Could this be a bug in Xen or is this an error on my part ?

Appreciate any help you guys can give me,

Jasper



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