APPLIED: [SRU][Cosmic][Bionic][PATCH v1 0/1] Console got stuck using serial tty after logout

[Kleber Souza]

On 12/12/18 3:13 PM, woodrow.shen at canonical.com wrote:
> From: Woodrow Shen <woodrow.shen at canonical.com>
>
> BugLink: https://bugs.launchpad.net/bugs/1808097
>
> [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
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/tty/tty_port.c?h=v4.20-rc6&id=2a48602615e0a2f563549c7d5c8d507f904cf96e
>
> [Regression Potential]
> Should be none, and it's regression becoz 4.4 kernel didn't have this case.
>
> Chanho Park (1):
>   tty: do not set TTY_IO_ERROR flag if console port
>
>  drivers/tty/tty_port.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
Applied to bionic/master-next and cosmic/master-next branches.

Thanks,
Kleber