On Fri, Mar 23, 2018 at 01:24:46PM +0100, Erik Skultety wrote: > On Thu, Mar 22, 2018 at 06:10:49PM +0200, Mathieu Tarral wrote: > > Hi ! > > > > I'm submitting my messages on this mailing list to request a bit of > > help on a case that I have > > where a Python application makes a call to virDomainIsActive, and the > > call never returns. > > > > I have tried to investigate, but as there are no debug symbols for > > libvirt on Debian Stretch, > > i can only have the following GDB backtrace: > > > > (gdb) bt > > #0 pthread_cond_wait@@GLIBC_2.3.2 () at > > ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185 > > #1 0x00007f49026f5b76 in virCondWait () from /usr/lib/libvirt.so.0 > > #2 0x00007f4902808bab in ?? () from /usr/lib/libvirt.so.0 > > #3 0x00007f490280a433 in virNetClientSendWithReply () from > > /usr/lib/libvirt.so.0 > > #4 0x00007f490280abe2 in virNetClientProgramCall () from /usr/lib/libvirt.so.0 > > #5 0x00007f49027e0ea4 in ?? () from /usr/lib/libvirt.so.0 > > #6 0x00007f49027ea1bb in ?? () from /usr/lib/libvirt.so.0 > > #7 0x00007f49027b0ef3 in virDomainIsActive () from /usr/lib/libvirt.so.0 > > #8 0x00007f4902b7fbd0 in libvirt_virDomainIsActive () from > > /usr/lib/python3/dist-packages/libvirtmod.cpython-35m-x86_64-linux-gnu.so > > #9 0x0000558eeec696df in PyCFunction_Call () at ../Objects/methodobject.c:109 > > > > The libvirt driver used is QEMU, and i have a specific monitoring in > > place using virtual machine introspection: > > https://github.com/KVM-VMI/kvm-vmi > > > > Now this specific monitoring somehow triggers this bug, and at this > > point, i don't know if > > it's a corner case in the libvirt QEMU driver or not. > > That's why i would like to have your lights on this. > > > > libvirt version: 3.0.0-4 > > > > -> Could you tell me where i should look in the code ? > > You're probably looking at virLogManagerDomain* methods located in > src/logging/log_manager.c and the wait call is issued from virNetClientIO. > > > -> Do you have more information about this virCondWait ? Which > > condition is it waiting for ? > > -> How can i get the symbols without having the recompile libvirt and > > install it system wide, erasing the binaries installed by the package > > ? > > To be honest, I think it's always worth debugging a custom built binary from > sources, since the debug symbols shipped via distro package are most likely > generated with optimizations which makes any kind of interactive debugging > painful. The problem is that you're going to built v3.0.0 tag on a new distro, > since new GCCs will complain about a lot of stuff, I looked at the code, tried > a few things, but honestly I didn't see a path where you could get to > virNetClientProgrammCall from virDomainIsActive (since I don't know what the > original call was), so unless you post a full backtrace, we can't help you much > here. That's easy - virDomainIsActive() calls into the driver APIs. This is client side trace, so will get into the remote driver client, which will then call virNetClientProgramCall. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :| -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list
