On Thu, Jun 10, 2010 at 9:07 PM, Daniel P. Berrange <berrange@redhat.com>wrote:
On Thu, Jun 10, 2010 at 08:57:15PM +0300, Emre Erenoglu wrote:
On Thu, Jun 10, 2010 at 5:02 PM, Matthias Bolte < matthias.bolte@googlemail.com> wrote:
2010/6/10 Emre Erenoglu <erenoglu@gmail.com>: The initscript explicitly starts the one in /usr/sbin. If you just start libvirtd manually without an absolute path then you'll start the one in /usr/local/sbin. This might explain why you cannot reproduce the segfault manually, but it doesn't explain why the segfault happens.
There's no other installation of libvirt in the system. I can also reproduce the same thing in all Pardus machines, so I believe it's something in libvirt not doing well with something else in our service init mechanisms.
I guess I'd put money on some environment variable causing trouble. It could be a *missing* environment variable that we expect to always be set, or something like that
Hi Daniel, thanks for your message. Yes, I did a small script file as you suggested and found out this environment while libvirtd was run: DBUS_STARTER_ADDRESS=unix:path=/var/run/dbus/system_bus_socket,guid=6c515f612162b05d554b59cd4c112d43 KRB5_KTNAME=/etc/libvirt/krb5.tab PWD=/ DBUS_STARTER_BUS_TYPE=system SHLVL=1 _=/usr/bin/env This looks very weak compared to the standard root environment that I pasted in my earlier message.
Could you provide a GDB backtrace of the segfault? The syslog entry only says that it crashed in libc, that's not enough information to debug the segfault.
Unfortunately, I can't find a related core file in the system. In fact, core file is not generated. I'll also try to fix this out and come back to the list.
Getting a backtrace would be simpler if you could reproduce the problem manually. In that case you could just start libvirtd in GDB. But getting a backtrace from a coredump will work too.
I can't reproduce the segfault when I run it manually. It only happens when it's run from this python script. I will try to initialize gdb inside the script and connect remotely to the gdb session, but it's getting a bit over my debugging capabilities :) For example, I don't know how to assign the symbols and source code etc from the package build directory to gdb.
Try creating a wrapper script, eg
mv /usr/sbin/libvirtd /usr/sbin/libvirtd.real cat > /usr/sbin/libvirtd <<EOF #!/bin/sh cd /tmp ulimited -c unlimited exec /usr/sbin/libvirtd.real EOF chmod +x /usr/sbin/libvirtd
That will hopefully give you a core dump in /tmp you can get get a stack trace from
Yes, I got the core file with the script. However, when I open the core file with gdb, and use bt command to get the backtrace, the only thing it tells me is this: Core was generated by `/usr/sbin/libvirtd --daemon'. Program terminated with signal 11, Segmentation fault. #0 0xb73ed8f3 in ?? () (gdb) bt Cannot access memory at address 0x810b9db Maybe I don't know enough of debugging as I know I have to see the code lines (somehow) at this segfault point. Could you guide me on that? Thanks, Br, Emre