tty: serial_core: add tty NULL check to uart_tx_stopped

Commit 761ed4a94582 ("tty: serial_core: convert uart_close to use
tty_port_close") created a case where a port used for a console does not
get shutdown on tty closing. Then a call to uart_tx_stopped() segfaults
because the tty is NULL. This could be fixed to restore old behavior,
but we also want to allow tty_ports to work without a tty attached. So
this change to allow a NULL tty_struct is needed either way.

Fixes: 761ed4a94582
("tty: serial_core: convert uart_close to use tty_port_close")
Reported-by: kernel test robot <xiaolong.ye@intel.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Change-Id: Ifbeeacc89d396b857332ce94cc2d77bdd6e12bb7
Git-repo: git://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git
Git-commit: a727b025f43d7952c0697562f5cecda9f42758aa
Signed-off-by: Lei wang <leiwan@codeaurora.org>
This commit is contained in:
Lei wang 2017-09-08 10:34:18 +08:00 committed by Gerrit - the friendly Code Review server
parent cb8f9c4da7
commit b8f1ab847c

View file

@ -402,7 +402,7 @@ int uart_resume_port(struct uart_driver *reg, struct uart_port *port);
static inline int uart_tx_stopped(struct uart_port *port)
{
struct tty_struct *tty = port->state->port.tty;
if (tty->stopped || port->hw_stopped)
if ((tty && tty->stopped) || port->hw_stopped)
return 1;
return 0;
}