I'm on a xenial ubuntu-desktop and have snappy dimension on classic installed. I was working on other things and apport popped up. The trigger seems to be the background snappy update task for ubuntu-core that triggers a reboot of ubuntu-core. Looking at my logs I see:
Mar 21 10:00:30 <hostname> systemd[1]: Started Ubuntu Core Snappy AutoUpdate. Mar 21 10:01:02 <hostname> systemd[1]: Mounting Squashfs mount unit for ubuntu-core... Mar 21 10:01:02 <hostname> systemd[1]: Mounted Squashfs mount unit for ubuntu-core. Mar 21 10:01:03 <hostname> snappy[25381]: Name Date Version Developer Mar 21 10:01:03 <hostname> snappy[25381]: ubuntu-core 2016-03-21 16.04-20160321-05-01 canonical! Mar 21 10:01:03 <hostname> snappy[25381]: Reboot to use ubuntu-core version 16.04-20160321-05-01. Mar 21 10:01:03 <hostname> snappy[25381]: Rebooting to satisfy updates for ubuntu-core Mar 21 10:01:03 <hostname> kernel: [85783.825747] systemd-logind[1101]: segfault at 0 ip 00007fc5cafcfd9e sp 00007ffc1cf 580b8 error 4 in libc-2.21.so[7fc5caf30000+1c0000] Mar 21 10:01:03 <hostname> systemd[1]: systemd-logind.service: Main process exited, code=dumped, status=11/SEGV Mar 21 10:01:03 <hostname> systemd[1]: systemd-logind.service: Unit entered failed state. Mar 21 10:01:03 <hostname> /usr/bin/snappy[25381]: main.go:50: DEBUG: [/usr/bin/snappy update --automatic-reboot] failed : failed to auto reboot: Failed to call ScheduleShutdown in logind, proceeding with immediate shutdown: Message re cipient disconnected from message bus without replying Mar 21 10:01:03 <hostname> snappy[25381]: failed to auto reboot: Failed to call ScheduleShutdown in logind, proceeding w ith immediate shutdown: Message recipient disconnected from message bus without replying Mar 21 10:01:03 <hostname> systemd[1]: systemd-logind.service: Failed with result 'core-dump'. Mar 21 10:01:03 <hostname> systemd[1]: snappy-autopilot.service: Main process exited, code=exited, status=1/FAILURE Mar 21 10:01:03 <hostname> systemd[1]: snappy-autopilot.service: Unit entered failed state. Mar 21 10:01:03 <hostname> systemd[1]: snappy-autopilot.service: Failed with result 'exit-code'. Mar 21 10:01:03 <hostname> systemd[1]: systemd-logind.service: Service has no hold-off time, scheduling restart. Mar 21 10:01:03 <hostname> systemd[1]: Stopped Login Service. Mar 21 10:01:03 <hostname> dbus[1163]: [system] Activating via systemd: service name='org.freedesktop.login1' unit='dbus -org.freedesktop.login1.service' Mar 21 10:01:03 <hostname> systemd[1]: Starting Login Service... Mar 21 10:01:03 <hostname> dbus[1163]: [system] Successfully activated service 'org.freedesktop.login1' Mar 21 10:01:03 <hostname> systemd[1]: Started Login Service. Mar 21 10:01:03 <hostname> systemd[1]: Started User Manager for UID 1000. Mar 21 10:01:03 <hostname> systemd[1]: Started User Manager for UID 119. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to systemd in Ubuntu. https://bugs.launchpad.net/bugs/1553040 Title: systemd-logind crashed with SIGSEGV Status in systemd package in Ubuntu: Confirmed Bug description: No idea what happened. ProblemType: Crash DistroRelease: Ubuntu 16.04 Package: systemd 229-2ubuntu1 [modified: usr/share/dbus-1/system-services/org.freedesktop.systemd1.service] ProcVersionSignature: Ubuntu 4.4.0-9.24-generic 4.4.3 Uname: Linux 4.4.0-9-generic x86_64 ApportVersion: 2.20-0ubuntu3 Architecture: amd64 Date: Fri Mar 4 07:01:44 2016 ExecutablePath: /lib/systemd/systemd-logind InstallationDate: Installed on 2015-04-30 (308 days ago) InstallationMedia: Ubuntu 15.04 "Vivid Vervet" - Release amd64 (20150422) MachineType: LENOVO 429149G ProcCmdline: /lib/systemd/systemd-logind ProcEnviron: LANG=de_DE.UTF-8 PATH=(custom, no user) ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-9-generic root=UUID=457973fc-512e-4b6a-b65b-85f15fa85b7b ro console=tty1 console=ttyS0 panic=-1 SegvAnalysis: Segfault happened at: 0x7fa6033fed9e <__strcmp_sse2_unaligned+30>: movdqu (%rsi),%xmm0 PC (0x7fa6033fed9e) ok source "(%rsi)" (0x00000000) not located in a known VMA region (needed readable region)! destination "%xmm0" ok SegvReason: reading NULL VMA Signal: 11 SourcePackage: systemd StacktraceTop: ?? () ?? () ?? () ?? () ?? () SystemImageInfo: Error: command ['system-image-cli', '-i'] failed with exit code 2: SystemdDelta: [EXTENDED] /lib/systemd/system/systemd-timesyncd.service → /lib/systemd/system/systemd-timesyncd.service.d/disable-with-time-daemon.conf [EXTENDED] /etc/systemd/system/display-manager.service → /lib/systemd/system/display-manager.service.d/xdiagnose.conf [EXTENDED] /lib/systemd/system/rc-local.service → /lib/systemd/system/rc-local.service.d/debian.conf 3 overridden configuration files found. Title: systemd-logind crashed with SIGSEGV UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: dmi.bios.date: 05/18/2011 dmi.bios.vendor: LENOVO dmi.bios.version: 8DET46WW (1.16 ) dmi.board.asset.tag: Not Available dmi.board.name: 429149G dmi.board.vendor: LENOVO dmi.board.version: Not Available dmi.chassis.asset.tag: No Asset Information dmi.chassis.type: 10 dmi.chassis.vendor: LENOVO dmi.chassis.version: Not Available dmi.modalias: dmi:bvnLENOVO:bvr8DET46WW(1.16):bd05/18/2011:svnLENOVO:pn429149G:pvrThinkPadX220:rvnLENOVO:rn429149G:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable: dmi.product.name: 429149G dmi.product.version: ThinkPad X220 dmi.sys.vendor: LENOVO To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1553040/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp

