Just re-discovered my own report here whilst trying to solve another occurrence of the same issue 18 months later.
Now with 18.04 and 4.15.0-56-lowlatency (amd64). With assistance of grawity in IRC #systemd I found some more information which might help narrow this down. $ uname -a Linux T300CHI 4.15.0-56-lowlatency #62-Ubuntu SMP PREEMPT Wed Jul 24 21:03:13 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux $ systemctl list-jobs JOB UNIT TYPE STATE 740792 systemd-suspend.service start running 740791 suspend.target start waiting 2 jobs listed. $ systemctl status systemd-suspend.service ◠systemd-suspend.service - Suspend Loaded: loaded (/lib/systemd/system/systemd-suspend.service; static; vendor preset: enabled) Active: activating (start) since Fri 2019-08-02 08:26:54 BST; 53min ago Docs: man:systemd-suspend.service(8) Main PID: 16968 (systemd-sleep) Tasks: 1 (limit: 4915) CGroup: /system.slice/systemd-suspend.service └─16968 /lib/systemd/systemd-sleep suspend Aug 02 08:26:54 T300CHI systemd[1]: Starting Suspend... Aug 02 08:26:55 T300CHI systemd-sleep[16968]: Suspending system... $ sudo cat /proc/$(pidof systemd-sleep)/stack [<0>] __vt_event_wait.isra.2.part.3+0x40/0x90 [<0>] vt_waitactive+0x7b/0xd0 [<0>] vt_move_to_console+0x46/0xc0 [<0>] pm_prepare_console+0x23/0x40 [<0>] pm_suspend+0x19c/0x3b0 [<0>] state_store+0x85/0xf0 [<0>] kobj_attr_store+0x12/0x20 [<0>] sysfs_kf_write+0x3c/0x50 [<0>] kernfs_fop_write+0x125/0x1a0 [<0>] __vfs_write+0x1b/0x40 [<0>] vfs_write+0xb1/0x1a0 [<0>] SyS_write+0x55/0xc0 [<0>] do_syscall_64+0x73/0x130 [<0>] entry_SYSCALL_64_after_hwframe+0x3d/0xa2 [<0>] 0xffffffffffffffff -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1744370 Title: 'systemd-sleep suspend' hung after an abortive suspend/resume To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1744370/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs