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

Message ID CAMPhdO-69ZP0T_MzfouWwvGOXb7D2f5q9VLLHVf+3HVw1nFSJQ@mail.gmail.com
State Accepted
Headers show

Commit Message

Eric Miao Dec. 26, 2011, 1:48 p.m. UTC 
---------- Forwarded message ----------
From: Eric Miao <eric.miao@linaro.org>
Date: Fri, Dec 23, 2011 at 5:39 AM
Subject: [PATCH] tty: serial: imx: move del_timer_sync() to avoid
potential deadlock
To: linux-kernel <linux-kernel@vger.kernel.org>
Cc: linux-arm-kernel <linux-arm-kernel@lists.infradead.org>, Eric Miao
<eric.miao@linaro.org>, Fabio Estevam <fabio.estevam@freescale.com>,
Shawn Guo <shawn.guo@linaro.org>, Sascha Hauer
<s.hauer@pengutronix.de>, Greg Kroah-Hartman <gregkh@suse.de>


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>
---
 drivers/tty/serial/imx.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

        */
@@ -934,8 +936,6 @@ 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.
        */
--
1.7.5.4
diff mbox

Patch

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 39bbce4..0f4ba21 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -904,6 +904,8 @@  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.