The libvirt-bin package from the ci-train ppa didn't fix my other problem (bug #1756981). libvirt-bin again changed pids after the virt-manager "crash".


grep libvirt /var/log/syslog shows when the version from the ppa segfaulted:

Mar 19 16:58:31 nsnx libvirtd[30256]: 2018-03-19 19:58:31.302+0000: 30272: info : libvirt version: 4.0.0, package: 1ubuntu6~ppa2 (Christian Ehrhardt <email address hidden> Mon, 19 Mar 2018 14:57:08 +0100)
Mar 19 16:58:31 nsnx libvirtd[30256]: 2018-03-19 19:58:31.302+0000: 30272: info : hostname: nsnx
Mar 19 16:58:31 nsnx libvirtd[30256]: 2018-03-19 19:58:31.302+0000: 30272: error : virPidFileAcquirePath:422 : Failed to acquire pid file '/var/lib/libvirt/qemu/capabilities.pidfile': Resource temporarily unavailable
Mar 19 16:58:31 nsnx libvirtd[30256]: 2018-03-19 19:58:31.909+0000: 30272: error : virDirOpenInternal:2840 : cannot open directory '/ds216/downloads/isos/ubuntu/14.04': No such file or directory
Mar 19 16:58:31 nsnx libvirtd[30256]: 2018-03-19 19:58:31.909+0000: 30272: error : storageDriverAutostartCallback:210 : internal error: Failed to autostart storage pool '14.04': cannot open directory '/ds216/downloads/isos/ubuntu/14.04': No such file or directory
Mar 19 16:58:31 nsnx libvirtd[30256]: 2018-03-19 19:58:31.910+0000: 30272: error : virDirOpenInternal:2840 : cannot open directory '/ds216/downloads/isos/ubuntu/16.04': No such file or directory
Mar 19 16:58:31 nsnx libvirtd[30256]: 2018-03-19 19:58:31.910+0000: 30272: error : storageDriverAutostartCallback:210 : internal error: Failed to autostart storage pool '16.04': cannot open directory '/ds216/downloads/isos/ubuntu/16.04': No such file or directory
Mar 19 17:04:48 nsnx kernel: [24991.495464] libvirtd[30258]: segfault at 0 ip 00007f3cee849020 sp 00007f3ce2016968 error 4 in libvirt.so.0.4000.0[7f3cee737000+3be000]
Mar 19 17:04:48 nsnx systemd[1]: libvirtd.service: Main process exited, code=killed, status=11/SEGV
Mar 19 17:04:48 nsnx systemd[1]: libvirtd.service: Failed with result 'signal'.
Mar 19 17:04:48 nsnx systemd[1]: libvirtd.service: Service hold-off time over, scheduling restart.
Mar 19 17:04:48 nsnx systemd[1]: libvirtd.service: Scheduled restart job, restart counter is at 1.
Mar 19 17:04:48 nsnx systemd[1]: libvirtd.service: Found left-over process 3027 (dnsmasq) in control group while starting unit. Ignoring.
Mar 19 17:04:48 nsnx systemd[1]: libvirtd.service: Found left-over process 3158 (dnsmasq) in control group while starting unit. Ignoring.
Mar 19 17:04:48 nsnx systemd[1]: libvirtd.service: Found left-over process 3160 (dnsmasq) in control group while starting unit. Ignoring.
Mar 19 17:04:48 nsnx systemd[1]: libvirtd.service: Found left-over process 3269 (dnsmasq) in control group while starting unit. Ignoring.
Mar 19 17:04:48 nsnx systemd[1]: libvirtd.service: Found left-over process 12043 (qemu-system-x86) in control group while starting unit. Ignoring.
Mar 19 17:04:49 nsnx dnsmasq[3158]: read /var/lib/libvirt/dnsmasq/default.addnhosts - 0 addresses
Mar 19 17:04:49 nsnx dnsmasq-dhcp[3158]: read /var/lib/libvirt/dnsmasq/default.hostsfile
Mar 19 17:04:49 nsnx dnsmasq[3269]: read /var/lib/libvirt/dnsmasq/pxe5.addnhosts - 0 addresses
Mar 19 17:04:49 nsnx dnsmasq[3027]: read /var/lib/libvirt/dnsmasq/fed10-0-7-0.addnhosts - 0 addresses
Mar 19 17:04:49 nsnx libvirtd[3819]: 2018-03-19 20:04:49.657+0000: 3835: info : libvirt version: 4.0.0, package: 1ubuntu6~ppa2 (Christian Ehrhardt <email address hidden> Mon, 19 Mar 2018 14:57:08 +0100)
Mar 19 17:04:49 nsnx libvirtd[3819]: 2018-03-19 20:04:49.657+0000: 3835: info : hostname: nsnx
Mar 19 17:04:49 nsnx libvirtd[3819]: 2018-03-19 20:04:49.657+0000: 3835: error : virDirOpenInternal:2840 : cannot open directory '/ds216/downloads/isos/ubuntu/16.04': No such file or directory
Mar 19 17:04:49 nsnx libvirtd[3819]: 2018-03-19 20:04:49.657+0000: 3835: error : storageDriverAutostartCallback:210 : internal error: Failed to autostart storage pool '16.04': cannot open directory '/ds216/downloads/isos/ubuntu/16.04': No such file or directory
Mar 19 17:04:49 nsnx libvirtd[3819]: 2018-03-19 20:04:49.657+0000: 3835: error : virDirOpenInternal:2840 : cannot open directory '/ds216/downloads/isos/ubuntu/14.04': No such file or directory
Mar 19 17:04:49 nsnx libvirtd[3819]: 2018-03-19 20:04:49.657+0000: 3835: error : storageDriverAutostartCallback:210 : internal error: Failed to autostart storage pool '14.04': cannot open directory '/ds216/downloads/isos/ubuntu/14.04': No such file or directory