From: Fabio Estevam <fabio.estevam@xxxxxxx>
Doing the following UART bind/unbind sequence on a i.mx platform causes
a kernel crash due to NULL pointer dereference:
echo 21f4000.serial > /sys/bus/platform/drivers/imx-uart/bind
echo 21f4000.serial > /sys/bus/platform/drivers/imx-uart/unbind
Fix this problem by adding NULL checks prior to calling release/request_port
ops.
Reported-by: Fugang Duan <fugang.duan@xxxxxxx>
Signed-off-by: Fabio Estevam <fabio.estevam@xxxxxxx>
---
Changes since v1:
- Add NULL checks prior to other release/request_port calls.
drivers/tty/serial/serial_core.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index a333c59..9fc1533 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -887,7 +887,7 @@ static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
/*
* Free and release old regions
*/
- if (old_type != PORT_UNKNOWN)
+ if (old_type != PORT_UNKNOWN && uport->ops->release_port)
uport->ops->release_port(uport);
uport->iobase = new_port;
@@ -900,7 +900,7 @@ static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
/*
* Claim and map the new regions
*/
- if (uport->type != PORT_UNKNOWN) {
+ if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {
retval = uport->ops->request_port(uport);
} else {
/* Always success - Jean II */
@@ -1125,7 +1125,7 @@ static int uart_do_autoconfig(struct tty_struct *tty,struct uart_state *state)
* If we already have a port type configured,
* we must release its resources.
*/
- if (uport->type != PORT_UNKNOWN)
+ if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
uport->ops->release_port(uport);
flags = UART_CONFIG_TYPE;
@@ -2897,7 +2897,7 @@ int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport)
/*
* Free the port IO and memory resources, if any.
*/
- if (uport->type != PORT_UNKNOWN)
+ if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
uport->ops->release_port(uport);
kfree(uport->tty_groups);
--
1.9.1
--
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