I'm seeing this same issue (hung syscall on VT) from systemd-sleep on a suspend operation with Xubuntu (and therefore lightdm). I see a similar stack-trace too. 18.04 with 4.15.0-56-lowlatency.
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1744370 apt list plymouth Listing... Done plymouth/bionic-updates,now 0.9.3-1ubuntu7.18.04.2 amd64 [installed,automatic] $ 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 Desktop Bugs, which is subscribed to gdm3 in Ubuntu. https://bugs.launchpad.net/bugs/1817738 Title: Can't change virtual terminal on login screen or when auto-login is enabled To manage notifications about this bug go to: https://bugs.launchpad.net/oem-priority/+bug/1817738/+subscriptions -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
