[libvirt-users] About debugging of libvirt.

[Dario Faggioli]

On mer, 2013-12-18 at 11:47 +0530, cool dharma06 wrote:
> i am using libvirt-1.1.4 with xen(libxl). When destroying the VM its
> showing the following error :
> 
> 
> virsh # destroy 4
> 
> error: Failed to destroy domain 4
> error: End of file while reading data: Input/output error
> error: One or more references were leaked after disconnect from the
> hypervisor
> error: Failed to reconnect to the hypervisor
> 
Libvirt 1.1.4 built from sources? Also, what version of Xen (and thus of
libxl)? Build from sources or installed via distro packages?
> 
> virsh # list
> error: failed to connect to the hypervisor
> error: no valid connection
> error: Failed to connect socket to '/var/run/libvirt/libvirt-sock':
> Connection refused
> 
Mmm... I'm doing some libvirt testing/development on the libxl driver
right in these days, and I've issued a lot of `virsh start' and `virsh
stop' without seeing anything like this (I'm on trunk for both libvirt
and xen, though).
> 
> already i send one request to this community to solve this problem.
> they suggested to do gdb.
> 
Well, sure gdb could be useful... But what about checking the logs? Look
in /var/log/libvirt/libxl.
> 
> Any guide to do the gdb libvirtd. By googling i did the following
> things:
> 
> 
> 1. i enable the logoutput and loglevel in libvirtd.conf
> 2. restarted the libvirtd with the changed configuration file.
> 3. ps -aux | grep libvirtd
> 4. gdb libvirtd pid
> 5. then what i have to do to find the reason for this error.
> 
You have to trigger the crash (e.g., by issuing the offending command in
another terminal window) and try to figure out where it is that libvirtd
died, check the backtrace, etc.

Once you have figured out that, you can set breakpoints right before the
statements where it crashes, and try to figure out (by looking at
variable values, etc) what is making it explode.

Again, I'd recommend checking the logs (first) to help with that.

Regards,
Dario


-- 
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)

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