From a5a2b13074fd8d290bad32a5b0a0c5be9f3a84fa Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Tue, 13 Sep 2016 00:23:42 +0300 Subject: [PATCH] serial: core: fix potential NULL pointer dereference The commit 761ed4a94582 ("tty: serial_core: convert uart_close to use tty_port_close") refactored uart_close() to use tty_port_close(). At the same time it introduced a potential NULL pointer dereference. Rearrange the code to avoid kernel crash. Fixes: 761ed4a94582 ("tty: serial_core: convert uart_close to use tty_port_close") Cc: Rob Herring Signed-off-by: Andy Shevchenko Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/serial_core.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 6b7f857fc3b0..6e4f63627479 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -1484,15 +1484,15 @@ static void uart_tty_port_shutdown(struct tty_port *port) struct uart_state *state = container_of(port, struct uart_state, port); struct uart_port *uport = uart_port_check(state); - spin_lock_irq(&uport->lock); /* * At this point, we stop accepting input. To do this, we * disable the receive line status interrupts. */ - WARN(!uport, "detached port still initialized!\n"); + if (WARN(!uport, "detached port still initialized!\n")) + return; + spin_lock_irq(&uport->lock); uport->ops->stop_rx(uport); - spin_unlock_irq(&uport->lock); uart_port_shutdown(port); -- 2.20.1