Console got stuck using serial tty after logout
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Fix Released
|
Undecided
|
Woodrow Shen | ||
Bionic |
Fix Released
|
Undecided
|
Unassigned | ||
Cosmic |
Fix Released
|
Undecided
|
Unassigned |
Bug Description
[Impact]
The agetty stopped working using serial tty when user logged out, especially if there is a remained process. The agetty failed to open tty device due to serial port used by previous process was not released.
[Test Case]
1. Run background processes from serial console
$ while true; do sleep 10; done &
2. Log out
$ logout
3. Read journal log by journalctl | tail
Jan 28 16:07:01 ubuntu systemd[1]: Stopped Serial Getty on ttyAMA0.
Jan 28 16:07:01 ubuntu systemd[1]: Started Serial Getty on ttyAMA0.
Jan 28 16:07:02 ubuntu agetty[1643]: /dev/ttyAMA0: not a tty
[Fix]
The upstream has a fix since 4.20-rc6, which turns off TTY_IO_ERROR flag if port comes from console. The commit is cherry-picked by
[Regression Potential]
Should be none, and it's regression becoz 4.4 kernel didn't have this case.
CVE References
Changed in linux (Ubuntu): | |
status: | New → Confirmed |
assignee: | nobody → Woodrow Shen (woodrow-shen) |
description: | updated |
Changed in linux (Ubuntu): | |
status: | Confirmed → In Progress |
Changed in linux (Ubuntu Bionic): | |
status: | New → Fix Committed |
Changed in linux (Ubuntu Cosmic): | |
status: | New → Fix Committed |
Changed in linux (Ubuntu): | |
status: | In Progress → Fix Committed |
Changed in linux (Ubuntu): | |
status: | Fix Committed → Fix Released |
This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification- needed- cosmic' to 'verification- done-cosmic' . If the problem still exists, change the tag 'verification- needed- cosmic' to 'verification- failed- cosmic' .
If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.
See https:/ /wiki.ubuntu. com/Testing/ EnableProposed for documentation how to enable and use -proposed. Thank you!