Commit 2a486026 authored Nov 22, 2018 by Chanho Park Committed by Greg Kroah-Hartman Nov 27, 2018

tty: do not set TTY_IO_ERROR flag if console port



Since Commit 761ed4a9 ('tty: serial_core: convert uart_close to use
tty_port_close') and Commit 4dda864d ('tty: serial_core: Fix serial
console crash on port shutdown), a serial port which is used as
console can be stuck when logging out if there is a remained process.
After logged out, agetty will try to grab the serial port but it will
be failed because the previous process did not release the port
correctly. To fix this, TTY_IO_ERROR bit should not be enabled of
tty_port_close if the port is console port.

Reproduce step:
- Run background processes from serial console
$ while true; do sleep 10; done &

- Log out
$ logout
-> Stuck

- 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

Fixes: 761ed4a9 ("tty: serial_core: convert uart_close to use tty_port_close")
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Rob Herring <robh@kernel.org>
Cc: Jiri Slaby <jslaby@suse.com>
Signed-off-by: Chanho Park <parkch98@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent ccda4af0

drivers/tty/tty_port.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -633,6 +633,7 @@ void tty_port_close(struct tty_port port, struct tty_struct tty,
		if (tty_port_close_start(port, tty, filp) == 0)
		return;
		tty_port_shutdown(port, tty);
		if (!port->console)
		set_bit(TTY_IO_ERROR, &tty->flags);
		tty_port_close_end(port, tty);
		tty_port_tty_set(port, NULL);

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