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Commit 7c61c3d8 authored by Peter Hurley's avatar Peter Hurley Committed by Greg Kroah-Hartman
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tty: Fix transient pty write() EIO 



Commit 69939035
('pty: Ignore slave pty close() if never successfully opened')
introduced a bug with ptys whereby a write() in parallel with an
open() on an existing pty could mistakenly indicate an I/O error.

Only indicate an I/O error if the condition on open() actually exists.

Reported-by: default avatarMarkus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: default avatarPeter Hurley <peter@hurleysoftware.com>
Tested-by: default avatarMikael Pettersson <mikpe@it.uu.se>
Cc: stable <stable@vger.kernel.org> # 3.9
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ef223fb3

drivers/tty/pty.c

+5 −8
Original line number Diff line number Diff line
@@ -244,14 +244,9 @@ static void pty_flush_buffer(struct tty_struct *tty) 


static int pty_open(struct tty_struct *tty, struct file *filp)

{

	int	retval = -ENODEV;



	if (!tty || !tty->link)

		goto out;



	set_bit(TTY_IO_ERROR, &tty->flags);

		return -ENODEV;



	retval = -EIO;

	if (test_bit(TTY_OTHER_CLOSED, &tty->flags))

		goto out;

	if (test_bit(TTY_PTY_LOCK, &tty->link->flags))
@@ -262,9 +257,11 @@ static int pty_open(struct tty_struct *tty, struct file *filp) 
	clear_bit(TTY_IO_ERROR, &tty->flags);

	clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);

	set_bit(TTY_THROTTLED, &tty->flags);

	retval = 0;

	return 0;



out:

	return retval;

	set_bit(TTY_IO_ERROR, &tty->flags);

	return -EIO;

}



static void pty_set_termios(struct tty_struct *tty,