tty: serial: imx: move del_timer_sync() to avoid potential deadlock

del_timer_sync() acquires its own lock and doesn't have to be nested
within the spinlock of sport->port.lock in imx_set_termios(),  which
will cause potential deadlock.  Fix this by moving it outside.

Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Eric Miao <eric.miao@linaro.org>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 6b98a52..0b7fed7 100644 (file)
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -932,6 +932,8 @@ imx_set_termios(struct uart_port *port, struct ktermios *termios,
                        ucr2 |= UCR2_PROE;
        }
 
+       del_timer_sync(&sport->timer);
+
        /*
         * Ask the core to calculate the divisor for us.
         */
@@ -962,8 +964,6 @@ imx_set_termios(struct uart_port *port, struct ktermios *termios,
                        sport->port.ignore_status_mask |= URXD_OVRRUN;
        }
 
-       del_timer_sync(&sport->timer);
-
        /*
         * Update the per-port timeout.
         */