From e9cef8625e997a5ade9cddd2d501257dfee7cb62 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Thu, 22 Jan 2015 12:24:31 -0500 Subject: [PATCH] serial: 8250: Prevent concurrent updates to shadow registers The port shadow registers, ->fcr and ->mcr, must be protected from concurrent updates. Relocate the shadow register updates in serial8250_do_set_termios() to the port lock critical section. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_core.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index 1449c56506b7..57d13b058a48 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -2549,6 +2549,15 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios, port->uartclk / 16); quot = serial8250_get_divisor(up, baud, &frac); + /* + * Ok, we're now changing the port state. Do it with + * interrupts disabled. + */ + serial8250_rpm_get(up); + spin_lock_irqsave(&port->lock, flags); + + up->lcr = cval; /* Save computed LCR */ + if (up->capabilities & UART_CAP_FIFO && port->fifosize > 1) { /* NOTE: If fifo_bug is not set, a user can set RX_trigger. */ if ((baud < 2400 && !up->dma) || up->fifo_bug) { @@ -2571,15 +2580,6 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios, up->mcr |= UART_MCR_AFE; } - /* - * Ok, we're now changing the port state. Do it with - * interrupts disabled. - */ - serial8250_rpm_get(up); - spin_lock_irqsave(&port->lock, flags); - - up->lcr = cval; /* Save computed LCR */ - /* * Update the per-port timeout. */ -- 2.20.1