Public bug reported: References: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=810660 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=866898
If X is running and you switch to a plain text console (ie ctrl-alt-f3), log in as a regular user, and then log out, the display switches back to the graphical login screen and locks up. The system is still functioning (can ssh in, etc) but the video output is frozen. The underlying cause is: https://gitlab.freedesktop.org/xorg/xserver/issues/492 However, the problem can at least be worked around by making clear_console switch to tty 6 and back instead of switching to 1 and back. This patch corrects the problem: --- bash-4.4.18.orig/debian/clear_console.c 2019-03-28 12:09:02.415907787 -0400 +++ bash-4.4.18/debian/clear_console.c 2019-03-28 12:08:11.984366858 -0400 @@ -205,7 +205,7 @@ #if defined(__linux__) num = vtstat.v_active; #endif - tmp_num = (num == 1 ? 2 : 1); + tmp_num = (num == 6 ? 5 : 6); /* switch vt to clear the scrollback buffer */ if (ioctl(fd, VT_ACTIVATE, tmp_num)) ** Affects: bash (Ubuntu) Importance: Undecided Status: New ** Patch added: "makes clear_console switch to either tty6 or tty5 instead of tty1/tty2" https://bugs.launchpad.net/bugs/1822184/+attachment/5250280/+files/fix-clear_console-GUI-lockup.patch -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1822184 Title: clear_console locks up video when X is running and you log out from a plain text console To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/bash/+bug/1822184/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs