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Commit e9cef862 authored by Peter Hurley's avatar Peter Hurley Committed by Greg Kroah-Hartman
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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: default avatarPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4516d50a

drivers/tty/serial/8250/8250_core.c

+9 −9
Original line number Diff line number Diff line
@@ -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.

	 */