Loop Mounted Device Issue?

[Peter Bryant <p.spamcatcher@rimuhosting.com>]

Hi.  We are running xen-3.0-testing.  We use loop back mounted file 
systems.  The server we are running restarts itself/crashes.  This seems 
to happen around setting up loop back devices.  (>63 loop back devices 
seems to trigger a crash, but we have seen then with fewer devices 
mounted as well).

We have swapped all hardware (bar the disks) to a new server.  Same 
issue.  I see no disk errors in the logs.

Does this problem ring any bells for anyone?  Else what sort of 
information can we provide that would assist someone in tracking down a 
potential bug/problem?  Some random info/log snippets follow.

We'll be trying out xen3-unstable/3.0.1 shortly.

Regards, Peter


# xm info
system                 : Linux
release                : 2.6.12.6-xen0
version                : #2 Thu Jan 26 01:17:22 UTC 2006
machine                : i686
nr_cpus                : 4
nr_nodes               : 1
sockets_per_node       : 2
cores_per_socket       : 1
threads_per_core       : 2
cpu_mhz                : 3000
hw_caps                : bfebfbff:20000000:00000000:00000080:0000641d
total_memory           : 6144
free_memory            : 2246
xen_major              : 3
xen_minor              : 0
xen_extra              : .0
xen_caps               : xen-3.0-x86_32p
platform_params        : virt_start=0xf5800000
xen_changeset          : Mon Dec 12 18:47:47 2005 +0100 8270:4ad23e798798
cc_compiler            : gcc version 3.4.4 20050721 (Red Hat 3.4.4-2)
cc_compile_by          : root
cc_compile_date        : Thu Jan 26 02:15:16 UTC 2006


[2006-01-26 20:48:33 xend] DEBUG (DevController:139) Waiting for 0.
[2006-01-26 20:48:33 xend] DEBUG (DevController:409) 
hotplugStatusCallback /local/domain/0/backend/vif/28/0/hotplug-status.
[2006-01-26 20:48:44 xend] ERROR (SrvBase:87) Request wait_for_devices 
failed.
Traceback (most recent call last):
   File "/usr/lib/python/xen/web/SrvBase.py", line 85, in perform
     return op_method(op, req)
   File "/usr/lib/python/xen/xend/server/SrvDomain.py", line 72, in 
op_wait_for_devices
     return self.dom.waitForDevices()
   File "/usr/lib/python/xen/xend/XendDomainInfo.py", line 1349, in 
waitForDevices
     self.waitForDevices_(c)
   File "/usr/lib/python/xen/xend/XendDomainInfo.py", line 977, in 
waitForDevices_
     return self.getDeviceController(deviceClass).waitForDevices()
   File "/usr/lib/python/xen/xend/server/DevController.py", line 135, in 
waitForDevices
     return map(self.waitForDevice, self.deviceIDs())
   File "/usr/lib/python/xen/xend/server/DevController.py", line 145, in 
waitForDevice
     raise VmError("Device %s (%s) could not be connected. "
VmError: Device 0 (vif) could not be connected. Hotplug scripts not working.


[2006-01-26 21:02:32 xend] DEBUG (blkif:24) exception looking up device 
number for xvda1: [Errno 2] No such file or directory
: '/dev/xvda1'
[2006-01-26 21:02:32 xend] DEBUG (DevController:104) DevController: 
writing {'virtual-device': '51713', 'backend-id': '0', 's
tate': '1', 'backend': '/local/domain/0/backend/vbd/30/51713'} to 
/local/domain/30/device/vbd/51713.
[2006-01-26 21:02:32 xend] DEBUG (DevController:106) DevController: 
writing {'domain': 'a360feedback.be', 'frontend': '/local
/domain/30/device/vbd/51713', 'dev': 'xvda1', 'state': '1', 'params': 
'/home/users/a360feedback.be/debian.sarge-2.ext3', 'mod
e': 'w', 'frontend-id': '30', 'type': 'file'} to 
/local/domain/0/backend/vbd/30/51713.
[2006-01-26 21:02:32 xend] DEBUG (blkif:24) exception looking up device 
number for xvda2: [Errno 2] No such file or directory
: '/dev/xvda2'


interface vif28.0 does not exist!
xenstore-read: couldn't read path backend/vbd/28/51713/node
xenstore-read: couldn't read path backend/vif/29/0/ip
xenstore-read: couldn't read path backend/vbd/29/51713/physical-device
mkdir: cannot create directory `/var/run/xen-hotplug/block': File exists
vif28.0: unknown interface: No such device
iptables: No chain/target/match by that name
iptables: Bad rule (does a matching rule exist in that chain?)
xenstore-read: couldn't read path backend/vbd/30/51713/physical-device
xenstore-read: couldn't read path backend/vif/30/0/ip