Patch "serial: core: lock port for stop_rx() in uart_suspend_port()" has been added to the 6.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    serial: core: lock port for stop_rx() in uart_suspend_port()

to the 6.4-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-lock-port-for-stop_rx-in-uart_suspend_po.patch
and it can be found in the queue-6.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit ae9f07cff1a8d4e034673a77b8c3e3e5c5561739
Author: John Ogness <john.ogness@xxxxxxxxxxxxx>
Date:   Thu May 25 11:37:53 2023 +0206

    serial: core: lock port for stop_rx() in uart_suspend_port()
    
    [ Upstream commit abcb0cf1f5b2d99b1d117a4dbce334120e358d6d ]
    
    The uarts_ops stop_rx() callback expects that the port->lock is
    taken and interrupts are disabled.
    
    Fixes: c9d2325cdb92 ("serial: core: Do stop_rx in suspend path for console if console_suspend is disabled")
    Signed-off-by: John Ogness <john.ogness@xxxxxxxxxxxxx>
    Reviewed-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
    Link: https://lore.kernel.org/r/20230525093159.223817-3-john.ogness@xxxxxxxxxxxxx
    Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 54e82f476a2cc..a664778492c46 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -2333,8 +2333,11 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
 	 * able to Re-start_rx later.
 	 */
 	if (!console_suspend_enabled && uart_console(uport)) {
-		if (uport->ops->start_rx)
+		if (uport->ops->start_rx) {
+			spin_lock_irq(&uport->lock);
 			uport->ops->stop_rx(uport);
+			spin_unlock_irq(&uport->lock);
+		}
 		goto unlock;
 	}