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tty: fix NULL pointer issue when tty_port ops is not set

Unlike 'client_ops' which is initialized to 'default_client_ops', the
port operations 'ops' may be left to NULL.
Check the 'ops' value before checking the 'ops->x' value.

Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Fabien Dessenne 2019-03-21 16:43:26 +01:00 committed by Greg Kroah-Hartman
parent 3ec8002951
commit f4e68d58cf

View File

@ -325,7 +325,7 @@ static void tty_port_shutdown(struct tty_port *port, struct tty_struct *tty)
if (tty && C_HUPCL(tty))
tty_port_lower_dtr_rts(port);
if (port->ops->shutdown)
if (port->ops && port->ops->shutdown)
port->ops->shutdown(port);
}
out:
@ -398,7 +398,7 @@ EXPORT_SYMBOL_GPL(tty_port_tty_wakeup);
*/
int tty_port_carrier_raised(struct tty_port *port)
{
if (port->ops->carrier_raised == NULL)
if (!port->ops || !port->ops->carrier_raised)
return 1;
return port->ops->carrier_raised(port);
}
@ -414,7 +414,7 @@ EXPORT_SYMBOL(tty_port_carrier_raised);
*/
void tty_port_raise_dtr_rts(struct tty_port *port)
{
if (port->ops->dtr_rts)
if (port->ops && port->ops->dtr_rts)
port->ops->dtr_rts(port, 1);
}
EXPORT_SYMBOL(tty_port_raise_dtr_rts);
@ -429,7 +429,7 @@ EXPORT_SYMBOL(tty_port_raise_dtr_rts);
*/
void tty_port_lower_dtr_rts(struct tty_port *port)
{
if (port->ops->dtr_rts)
if (port->ops && port->ops->dtr_rts)
port->ops->dtr_rts(port, 0);
}
EXPORT_SYMBOL(tty_port_lower_dtr_rts);
@ -684,7 +684,7 @@ int tty_port_open(struct tty_port *port, struct tty_struct *tty,
if (!tty_port_initialized(port)) {
clear_bit(TTY_IO_ERROR, &tty->flags);
if (port->ops->activate) {
if (port->ops && port->ops->activate) {
int retval = port->ops->activate(port, tty);
if (retval) {
mutex_unlock(&port->mutex);