pty: Ignore slave pty close() if never successfully opened (69939035) · Commits · 戴 / test

If the master and slave ptys are opened in parallel, the slave open fails because the pty is still locked. This is as designed. However, pty_close() is still called for the slave pty which sets TTY_OTHER_CLOSED in the master pty. This can cause the master open to fail as well. Use a common pattern in other tty drivers by setting TTY_IO_ERROR until the open is successful and only closing the pty if not set. Note: the master pty always closes regardless of whether the open was successful, so that proper cleanup can occur. Signed-off-by:

Peter Hurley <peter@hurleysoftware.com> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/pty.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -38,9 +38,12 @@ static void pty_close(struct tty_struct tty, struct file filp)
		if (tty->driver->subtype == PTY_TYPE_MASTER)
		WARN_ON(tty->count > 1);
		else {
		if (test_bit(TTY_IO_ERROR, &tty->flags))
		return;
		if (tty->count > 2)
		return;
		}
		set_bit(TTY_IO_ERROR, &tty->flags);
		wake_up_interruptible(&tty->read_wait);
		wake_up_interruptible(&tty->write_wait);
		tty->packet = 0;
		@@ -246,6 +249,8 @@ static int pty_open(struct tty_struct tty, struct file filp)
		if (!tty \|\| !tty->link)
		goto out;

		set_bit(TTY_IO_ERROR, &tty->flags);

		retval = -EIO;
		if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
		goto out;
		@@ -254,6 +259,7 @@ static int pty_open(struct tty_struct tty, struct file filp)
		if (tty->link->count != 1)
		goto out;

		clear_bit(TTY_IO_ERROR, &tty->flags);
		clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
		set_bit(TTY_THROTTLED, &tty->flags);
		retval = 0;

Admin message