diff options
| -rw-r--r-- | drivers/char/tty_io.c | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index 18085a20df2..b4f37c65b95 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -2740,18 +2740,21 @@ static int tiocsti(struct tty_struct *tty, char __user *p) * @tty; tty * @arg: user buffer for result * - * Copies the kernel idea of the window size into the user buffer. No - * locking is done. + * Copies the kernel idea of the window size into the user buffer. * - * FIXME: Returning random values racing a window size set is wrong - * should lock here against that + * Locking: tty->termios_sem is taken to ensure the winsize data + * is consistent. */ static int tiocgwinsz(struct tty_struct *tty, struct winsize __user * arg) { - if (copy_to_user(arg, &tty->winsize, sizeof(*arg))) - return -EFAULT; - return 0; + int err; + + down(&tty->termios_sem); + err = copy_to_user(arg, &tty->winsize, sizeof(*arg)); + up(&tty->termios_sem); + + return err ? -EFAULT: 0; } /** |