Today, after making some updates the issue still exists, but the shutdown screen got a little bit more verbose.
It tells me "A stop job is running for Light Display Manager" followed by the original error from this issue. If i do the following i can shut down: 1) sudo systemctl stop lightdm.service 2) switch to tty1 (ctrl+alt+f1) 3) sudo poweroff If i type "sudo systemctl stop lightdm.service && sudo poweroff" it wont work The lightdm logs only contain 1 non-debug output: [+33.52s] CRITICAL: session_get_login1_session_id: assertion 'session != NULL' failed The lightdm/x-0.log.1.gz contains some errors too Errors from xkbcomp are not fatal to the X server (EE) (EE) Backtrace: (EE) 0: /usr/lib/xorg/Xorg (xorg_backtrace+0x4e) [0x55b252dc7c6e] (EE) 1: /usr/lib/xorg/Xorg (0x55b252c15000+0x1b6ff9) [0x55b252dcbff9] (EE) 2: /lib/x86_64-linux-gnu/libc.so.6 (0x7f68dad65000+0x354b0) [0x7f68dad9a4b0] (EE) 3: /usr/lib/xorg/modules/libfb.so (_fbGetWindowPixmap+0xd) [0x7f68d4028bdd] (EE) 4: /usr/lib/xorg/Xorg (0x55b252c15000+0x1353d7) [0x55b252d4a3d7] (EE) 5: /usr/lib/xorg/Xorg (0x55b252c15000+0x1354a5) [0x55b252d4a4a5] (EE) 6: /usr/lib/xorg/Xorg (0x55b252c15000+0x135c12) [0x55b252d4ac12] (EE) 7: /usr/lib/xorg/Xorg (0x55b252c15000+0x1347c3) [0x55b252d497c3] (EE) 8: /usr/lib/xorg/Xorg (0x55b252c15000+0xe4c58) [0x55b252cf9c58] (EE) 9: /usr/lib/xorg/Xorg (0x55b252c15000+0x132b64) [0x55b252d47b64] (EE) 10: /usr/lib/xorg/Xorg (0x55b252c15000+0x57f17) [0x55b252c6cf17] (EE) 11: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xf0) [0x7f68dad85830] (EE) 12: /usr/lib/xorg/Xorg (_start+0x29) [0x55b252c57069] (EE) (EE) Segmentation fault at address 0x10 (EE) Fatal server error: (EE) Caught signal 11 (Segmentation fault). Server aborting (EE) (EE) Both logs contain the following strings (maybe some redirected input?): ^@^@^@^@^@ (this goes on for some time) I hope this is of some help for you -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1530405 Title: NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [kerneloops:814] To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1530405/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
