Re: [libvirt] Trying to debug "Received unexpected event 3" from libvirt

On Fri, Jan 8, 2016 at 7:00 PM, Michal Privoznik <mprivozn(a)redhat.com&gt; wrote: > > On 30.12.2015 11:30, Yaniv Kaul wrote: >> > > Hi, >> > > > > > > Hey, > > > > sorry for getting to you so late. > > >> > > I'm trying to debug this issue, which may be affecting my inability to >> > > perform live snapshot. >> > > 1. I'm not sure what 'Waking up a tragedian" in the debug log means - > > what >> > > exactly is a tragedian? > > > > > > It's the thread that has issued the change state API (shutdown, reboot, > > ..) and it's waiting for confirmation on the monitor. For instance, mgmt > > app issues virDomainPMSuspendForDuration() which in qemu driver is > > implemented via some agent calls. So the flow is like this: > > > > 1) the control gets to qemuDomainPMSuspendForDuration() > > 2) libvirt does some checks and issues 'guest-suspend-disk' command (or > > corresponding command to the selected target). > > 3) qemu-ga running inside guest tries (!) to suspend the guest (it may > > not necessarily succeed) > > 4) meanwhile, as guest is writing something onto disk (saving its RAM - > > but one is unable to tell from outside), the libvirt API is blocked > > 5) finally, guest kernel calls 'HALT' to which qemu responds by sending > > libvirt 'RESET' event > > 6) the libvirt event loop finds out that an event occurred on the domain > > monitor and calls callback > > 7) the callback will wake up the sleeping API if the event the API is > > waiting for matches the one obtained on the monitor > > >> > > 2. In any case, it'd be great if the WARN would mention mon->await_event > > - >> > > is it the event libvirt is actually waiting for? > > > > Sure, that would be much more helpful - mind posting a patch? > > Attached and tested. I can't post it properly, as the git is a bit 'dirty' with some po files that I can't clean: On branch workbranch Your branch is up-to-date with 'origin/master'. Changes not staged for commit: (use "git add <file>..." to update what will be committed) (use "git checkout -- <file>..." to discard changes in working directory) modified: po/ar.po modified: po/as.po modified: po/bg.po modified: po/bn.po modified: po/bn_IN.po modified: po/bs.po modified: po/ca.po modified: po/cs.po modified: po/cy.po modified: po/da.po modified: po/de.po modified: po/el.po modified: po/en_GB.po modified: po/es.po modified: po/et.po modified: po/fi.po modified: po/fr.po modified: po/gl.po modified: po/gu.po modified: po/he.po modified: po/hi.po

... Thanks, Y. >> > > >> > > (Both from qemu/qemu_agent.c) >> > > 3. I reckon event 3 is QEMU_AGENT_EVENT_RESET ? (from qemu/qemu_agent.h) >> > > > > > > Correct. > > >> > > 4. I'm also getting 'End of file while reading data: Input/output error' >> > > messages, not sure what they mean yet. > > > > > > Usually they mean crashing daemon. If you are able to get a stacktrace > > please do share it somewhere. > > > > Michal > > qemu_agent.c.diff diff --git a/src/qemu/qemu_agent.c b/src/qemu/qemu_agent.c index f979f82..924c177 100644 --- a/src/qemu/qemu_agent.c +++ b/src/qemu/qemu_agent.c @@ -1241,7 +1241,7 @@ void qemuAgentNotifyEvent(qemuAgentPtr mon, } } else { /* shouldn't happen but one never knows */ - VIR_WARN("Received unexpected event %d", event); + VIR_WARN("Received unexpected event %d (expected %d)", event, mon->await_event); } }