** No longer affects: linux (Ubuntu Bionic) ** No longer affects: linux (Ubuntu)
** Changed in: gdm3 (Ubuntu) Importance: Undecided => Medium -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gdm3 in Ubuntu. https://bugs.launchpad.net/bugs/1817738 Title: Can't change virtual terminal when auto-login is enabled Status in OEM Priority Project: New Status in gdm3 package in Ubuntu: Fix Released Status in gdm3 source package in Bionic: Fix Committed Bug description: [Impact] When AutomaticLogin is enable in gdm3. The "chvt" command hangs forever, preventing from changing foreground virtual terminal. [Test case] 1) Install Bionic/18.04LTS Desktop 2) Enable AutomaticLogin 2.1) Modify /etc/gdm3/custom.conf # Enabling automatic login AutomaticLoginEnable = true AutomaticLogin = <YOUR_USER> 3) Reboot your system and make sure AutoLogin works by not requesting password before opening the <YOUR_USER> session. 4) Print active VT $ sudo fgconsole Without the fix, it will be "1". # BAD With the fix, it will be "2". # GOOD 5) sudo chvt 4 ## chvt will hang here. Verification can be made from a 2nd terminal, run : $ cat /proc/$(pidof chvt)/stack [<0>] __vt_event_wait.isra.2.part.3+0x40/0x90 [<0>] vt_waitactive+0x80/0xd0 [<0>] vt_ioctl+0xd26/0x1140 [<0>] tty_ioctl+0xf6/0x8c0 [<0>] do_vfs_ioctl+0xa8/0x630 [<0>] SyS_ioctl+0x79/0x90 [<0>] do_syscall_64+0x73/0x130 [<0>] entry_SYSCALL_64_after_hwframe+0x3d/0xa2 [<0>] 0xffffffffffffffff It's basically waiting for the VT to be activated, but it never happens. [Potential regression] Low. Current gdm3 run autologin display on tty1. tty1 is really meant for the login screen. This commit changes autologin to not use the initial vt. If one switch to tty1, the next VT switch attempt will hangs again and one won't be able to switch it. tty1 is really the problem here, so by forcing the autologin to not use tty1 we improve the current behaviour where we can't switch VTs at all when autologin is enabled. The tty1 behaviour will still need (normal behaviour or not ???) to be investigated, but not mandatory required for the sake of this SRU IMHO. I suspect systemd-logind to be the reason of the tty1 behaviour: # ps root 1350 1 0 Mar03 ? 00:00:03 /lib/systemd/systemd-logind #lsof systemd-l 1350 root 24u CHR 4,1 0t0 45 /dev/tty1 But I haven't dig much in it for now. So the fix will works as long as one doesn't do run on tty1. Exactly like when autologin isn't enable. * From a machine with autologin enable: /etc/gdm3/customer.conf # Enabling automatic login AutomaticLoginEnable = true AutomaticLogin = user1 $ sudo fgconsole 1 * From a machine with autologin disable: /etc/gdm3/customer.conf # Enabling automatic login # AutomaticLoginEnable = true # AutomaticLogin = user1 $ sudo fgconsole 2 [Other information] * Upstream fix: https://github.com/GNOME/gdm/commit/39fb4ff6 $ git describe --contains 39fb4ff6 3.30.1~2^2~3 $ rmadision gdm3 ==> gdm3 | 3.28.3-0ubuntu18.04.4 | bionic-updates | ... gdm3 | 3.30.1-1ubuntu5 | cosmic | ... gdm3 | 3.30.1-1ubuntu5 | disco | ... gdm3 | 3.30.1-1ubuntu5.1 | cosmic-security | ... gdm3 | 3.30.1-1ubuntu5.1 | cosmic-updates | ... gdm3 | 3.31.4+git20190225-1ubuntu1 | disco-proposed | ... [Original Description] sudo strace chvt 4 execve("/bin/chvt", ["chvt", "4"], 0x7ffd63e5c758 /* 17 vars */) = 0 brk(NULL) = 0x561e18430000 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=74655, ...}) = 0 mmap(NULL, 74655, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f5059e7d000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\260\34\2\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=2030544, ...}) = 0 mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f5059e7b000 mmap(NULL, 4131552, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f5059878000 mprotect(0x7f5059a5f000, 2097152, PROT_NONE) = 0 mmap(0x7f5059c5f000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1e7000) = 0x7f5059c5f000 mmap(0x7f5059c65000, 15072, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f5059c65000 close(3) = 0 arch_prctl(ARCH_SET_FS, 0x7f5059e7c500) = 0 mprotect(0x7f5059c5f000, 16384, PROT_READ) = 0 mprotect(0x561e17e87000, 4096, PROT_READ) = 0 mprotect(0x7f5059e90000, 4096, PROT_READ) = 0 munmap(0x7f5059e7d000, 74655) = 0 brk(NULL) = 0x561e18430000 brk(0x561e18451000) = 0x561e18451000 openat(AT_FDCWD, "/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=10281936, ...}) = 0 mmap(NULL, 10281936, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f5058ea9000 close(3) = 0 openat(AT_FDCWD, "/proc/self/fd/0", O_RDWR) = 3 ioctl(3, TCGETS, {B38400 opost isig icanon echo ...}) = 0 ioctl(3, KDGKBTYPE, 0x7ffdcdb0efa7) = -1 ENOTTY (Inappropriate ioctl for device) close(3) = 0 openat(AT_FDCWD, "/dev/tty", O_RDWR) = 3 ioctl(3, TCGETS, {B38400 opost isig icanon echo ...}) = 0 ioctl(3, KDGKBTYPE, 0x7ffdcdb0efa7) = -1 ENOTTY (Inappropriate ioctl for device) close(3) = 0 openat(AT_FDCWD, "/dev/tty0", O_RDWR) = 3 ioctl(3, TCGETS, {B38400 opost isig icanon echo ...}) = 0 ioctl(3, KDGKBTYPE, 0x7ffdcdb0efa7) = 0 ioctl(3, VT_ACTIVATE, 0x4) = 0 ioctl(3, VT_WAITACTIVE, 0x4 VT_ACTIVATE will cause a switch to VT number. VT_WAITACTIVE will sleep/wait until the specified VT has been activated. $ sudo cat /proc/$(pidof chvt)/stack [<0>] __vt_event_wait.isra.2.part.3+0x40/0x90 [<0>] vt_waitactive+0x80/0xd0 [<0>] vt_ioctl+0xd26/0x1140 [<0>] tty_ioctl+0xf6/0x8c0 [<0>] do_vfs_ioctl+0xa8/0x630 [<0>] SyS_ioctl+0x79/0x90 [<0>] do_syscall_64+0x73/0x130 [<0>] entry_SYSCALL_64_after_hwframe+0x3d/0xa2 [<0>] 0xffffffffffffffff Enable debuglogs doesn't provide additional details. As soon as auto-login is turned off, chvt is back to normal. The above has been reproduced on Ubuntu: - Ubuntu Bionic w/ gdm3 3.28.3 & kbd 2.0.4 To manage notifications about this bug go to: https://bugs.launchpad.net/oem-priority/+bug/1817738/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
