From 22077b091a4720d4336bd806e9c93b2a81fcc38a Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Wed, 15 Mar 2017 12:00:23 +0100 Subject: [PATCH] tty: serial_core, remove state checks in uart_poll* Coverity complains about uart_state checks in polling functions. And it is indeed correct. We do something like this: struct uart_state *state = drv->state + line; if (!state) return; Adding 'line' to drv->state would move the potential NULL pointer to something near NULL and the check is useless. Even if we checked pure drv->state, nothing guarantees it is not freed and NULLed after the check. So if the only user of this interface (kgdboc) needs to assure something, this is neither the correct thing, nor place to do so. Signed-off-by: Jiri Slaby Cc: linux-serial@vger.kernel.org Cc: Jason Wessel Cc: kgdb-bugreport@lists.sourceforge.net Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/serial_core.c | 17 +++++------------ 1 file changed, 5 insertions(+), 12 deletions(-) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 3fe56894974a..0fb3f7cce62a 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -2331,9 +2331,6 @@ static int uart_poll_init(struct tty_driver *driver, int line, char *options) int flow = 'n'; int ret = 0; - if (!state) - return -1; - tport = &state->port; mutex_lock(&tport->mutex); @@ -2368,13 +2365,12 @@ static int uart_poll_get_char(struct tty_driver *driver, int line) struct uart_port *port; int ret = -1; - if (state) { - port = uart_port_ref(state); - if (port) { - ret = port->ops->poll_get_char(port); - uart_port_deref(port); - } + port = uart_port_ref(state); + if (port) { + ret = port->ops->poll_get_char(port); + uart_port_deref(port); } + return ret; } @@ -2384,9 +2380,6 @@ static void uart_poll_put_char(struct tty_driver *driver, int line, char ch) struct uart_state *state = drv->state + line; struct uart_port *port; - if (!state) - return; - port = uart_port_ref(state); if (!port) return; -- 2.20.1