serial: core: lock port for start_rx() in uart_resume_port()

[ Upstream commit 51e45fba14bf08b66bca764a083c7f2e2ff62f01 ]

The only user of the start_rx() callback (qcom_geni) directly calls
its own stop_rx() callback. Since stop_rx() requires that the
port->lock is taken and interrupts are disabled, the start_rx()
callback has the same requirement.

Fixes: cfab87c2c271 ("serial: core: Introduce callback for start_rx and do stop_rx in suspend only if this callback implementation is present.")
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20230525093159.223817-5-john.ogness@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index b0a4677..2cc5c68 100644 (file)
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -2431,8 +2431,11 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
                if (console_suspend_enabled)
                        uart_change_pm(state, UART_PM_STATE_ON);
                uport->ops->set_termios(uport, &termios, NULL);
-               if (!console_suspend_enabled && uport->ops->start_rx)
+               if (!console_suspend_enabled && uport->ops->start_rx) {
+                       spin_lock_irq(&uport->lock);
                        uport->ops->start_rx(uport);
+                       spin_unlock_irq(&uport->lock);
+               }
                if (console_suspend_enabled)
                        console_start(uport->cons);
        }