Re: trying to debug xen4 & qemu-dm, Xen reports "core dump failed"

[0bo0 <0.bugs.only.0@gmail.com>]

On Tue, Jan 26, 2010 at 1:38 PM, Keir Fraser <keir.fraser@eu.citrix.com> wrote:
> As root:
>    echo '/var/core/core.%e.%u.%p' > /proc/sys/kernel/core_pattern
>
> Now try starting your guest. It fails, and hopefully you have a core file in
> /var/core/. You can load it into gdb as 'gdb /usr/lib/xen/qemu-dm
> /var/core/name-of-core-file' and then execute bt command at the gdb prompt.
> That hopefully tells us where qemu-dm crashed.


bash
ulimit -c unlimited
echo '/var/core/core.%e.%u.%p' > /proc/sys/kernel/core_pattern
mkdir -p /var/core
cat /proc/sys/kernel/core_pattern
/var/core/core.%e.%u.%p

xm create /etc/xen/vm/test.cfg
  Using config file "/etc/xen/vm/test.cfg".
  Error: Domain 'test' does not exist.

ls -al /var/core
  total 8
  drwxr-xr-x  2 root root 4096 2010-01-26 13:48 ./
  drwxr-xr-x 18 root root 4096 2010-01-26 13:48 ../

@ syslog, though, i do see ....

Jan 26 14:09:17 server kernel: [  547.023464] kjournald starting.
Commit interval 15 seconds
Jan 26 14:09:17 server kernel: [  547.118565] EXT3-fs: mounted
filesystem with ordered data mode.
Jan 26 14:09:18 server logger: /etc/xen/scripts/block: add
XENBUS_PATH=backend/vbd/3/51712
Jan 26 14:09:18 server logger: /etc/xen/scripts/block: add
XENBUS_PATH=backend/vbd/3/51744
Jan 26 14:09:18 server logger: /etc/xen/scripts/block: add
XENBUS_PATH=backend/vbd/3/51728
Jan 26 14:09:18 server kernel: [  548.456142] qemu-dm[6791]: segfault
at 7fff7ee4169a ip 000000000047b974 sp 00007fff7ee40210 error 4 in
qemu-dm[400000+10b000]
Jan 26 14:09:18 server logger: /etc/xen/scripts/vif-bridge: online
XENBUS_PATH=backend/vif/3/0
Jan 26 14:09:18 server kernel: [  548.697863] device vif3.0 entered
promiscuous mode
Jan 26 14:09:19 server kernel: [  548.828028] br02: port 1(vif3.0)
entering forwarding state
Jan 26 14:09:19 server kernel: [  548.984448] physdev match: using
--physdev-out in the OUTPUT, FORWARD and POSTROUTING chains for
non-bridged traffic is not supported anymore.
Jan 26 14:09:19 server logger: /etc/xen/scripts/vif-bridge: Successful
vif-bridge online for vif3.0, bridge br02.
Jan 26 14:09:19 server logger: /etc/xen/scripts/vif-bridge: Writing
backend/vif/3/0/hotplug-status connected to xenstore.
Jan 26 14:09:19 server logger: /etc/xen/scripts/block: Writing
backend/vbd/3/51712/physical-device fd:d to xenstore.
Jan 26 14:09:19 server kernel: [  549.267962] (cdrom_add_media_watch()
file=/usr/src/packages/BUILD/kernel-xen-2.6.31.8/linux-2.6.31/drivers/xen/blkback/cdrom.c,
line=108) nodename:backend/vbd/3/51712
Jan 26 14:09:19 server kernel: [  549.474577] (cdrom_is_type()
file=/usr/src/packages/BUILD/kernel-xen-2.6.31.8/linux-2.6.31/drivers/xen/blkback/cdrom.c,
line=95) type:0
Jan 26 14:09:19 server logger: /etc/xen/scripts/block: Writing
backend/vbd/3/51712/hotplug-status connected to xenstore.
Jan 26 14:09:20 server logger: /etc/xen/scripts/block: Writing
backend/vbd/3/51728/physical-device fd:e to xenstore.
Jan 26 14:09:20 server kernel: [  550.443509] (cdrom_add_media_watch()
file=/usr/src/packages/BUILD/kernel-xen-2.6.31.8/linux-2.6.31/drivers/xen/blkback/cdrom.c,
line=108) nodename:backend/vbd/3/51728
Jan 26 14:09:20 server kernel: [  550.657671] (cdrom_is_type()
file=/usr/src/packages/BUILD/kernel-xen-2.6.31.8/linux-2.6.31/drivers/xen/blkback/cdrom.c,
line=95) type:0
Jan 26 14:09:20 server logger: /etc/xen/scripts/block: Writing
backend/vbd/3/51728/hotplug-status connected to xenstore.
Jan 26 14:09:21 server logger: /etc/xen/scripts/xen-hotplug-cleanup:
XENBUS_PATH=backend/vkbd/3/0
Jan 26 14:09:21 server logger: /etc/xen/scripts/xen-hotplug-cleanup:
XENBUS_PATH=backend/console/3/0
Jan 26 14:09:22 server kernel: [  552.224799] br02: port 1(vif3.0)
entering disabled state
Jan 26 14:09:22 server kernel: [  552.335801] br02: port 1(vif3.0)
entering disabled state
Jan 26 14:09:22 server logger: /etc/xen/scripts/xen-hotplug-cleanup:
XENBUS_PATH=backend/vfb/3/0
Jan 26 14:09:22 server logger: /etc/xen/scripts/block: remove
XENBUS_PATH=backend/vbd/3/51728
Jan 26 14:09:22 server logger: /etc/xen/scripts/block: remove
XENBUS_PATH=backend/vbd/3/51712
Jan 26 14:09:22 server logger: /etc/xen/scripts/vif-bridge: offline
XENBUS_PATH=backend/vif/3/0
Jan 26 14:09:22 server logger: /etc/xen/scripts/xen-hotplug-cleanup:
XENBUS_PATH=backend/vbd/3/51728
Jan 26 14:09:22 server logger: /etc/xen/scripts/xen-hotplug-cleanup:
XENBUS_PATH=backend/vbd/3/51712
Jan 26 14:09:22 server logger: /etc/xen/scripts/vif-bridge: brctl
delif br02 vif3.0 failed
Jan 26 14:09:22 server logger: /etc/xen/scripts/vif-bridge: ifconfig
vif3.0 down failed
Jan 26 14:09:22 server kernel: [  552.662465] physdev match: using
--physdev-out in the OUTPUT, FORWARD and POSTROUTING chains for
non-bridged traffic is not supported anymore.
Jan 26 14:09:22 server logger: /etc/xen/scripts/vif-bridge: Successful
vif-bridge offline for vif3.0, bridge br02.
Jan 26 14:09:22 server logger: /etc/xen/scripts/xen-hotplug-cleanup:
XENBUS_PATH=backend/vif/3/0
Jan 26 14:09:23 server logger: /etc/xen/scripts/block: Writing
backend/vbd/3/51744/physical-device fd:f to xenstore.
Jan 26 14:09:23 server logger: /etc/xen/scripts/block: Writing
backend/vbd/3/51744/hotplug-status connected to xenstore.
Jan 26 14:09:23 server logger: /etc/xen/scripts/block: remove
XENBUS_PATH=backend/vbd/3/51744
Jan 26 14:09:23 server logger: /etc/xen/scripts/xen-hotplug-cleanup:
XENBUS_PATH=backend/vbd/3/51744