Patch "serial: core: mark port as initialized after successful IRQ change" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

serial: core: mark port as initialized after successful IRQ change

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
serial-core-mark-port-as-initialized-after-successful-irq-change.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Sebastian Andrzej Siewior <[email protected]>
Date: Thu, 11 Jan 2018 18:57:26 +0100
Subject: serial: core: mark port as initialized after successful IRQ change

From: Sebastian Andrzej Siewior <[email protected]>

commit 44117a1d1732c513875d5a163f10d9adbe866c08 upstream.

setserial changes the IRQ via uart_set_info(). It invokes uart_shutdown() which free the current used IRQ and clear TTY_PORT_INITIALIZED. It will then update the IRQ number and invoke uart_startup() before returning to the caller leaving TTY_PORT_INITIALIZED cleared.

The next open will crash with
| list_add double add: new=ffffffff839fcc98, prev=ffffffff839fcc98, next=ffffffff839fcc98. since the close from the IOCTL won't free the IRQ (and clean the list)
due to the TTY_PORT_INITIALIZED check in uart_shutdown().

There is same pattern in uart_do_autoconfig() and I *think* it also needs to set TTY_PORT_INITIALIZED there.
Is there a reason why uart_startup() does not set the flag by itself after the IRQ has been acquired (since it is cleared in uart_shutdown)?

---
 drivers/tty/serial/serial_core.c |    2 ++
 1 file changed, 2 insertions(+)

@@ -987,6 +987,8 @@ static int uart_set_info(struct tty_stru
 		}
 	} else {
 		retval = uart_startup(tty, state, 1);
+		if (retval == 0)
+			tty_port_set_initialized(port, true);
 		if (retval > 0)
 			retval = 0;
 	}

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/serial-core-mark-port-as-initialized-after-successful-irq-change.patch