| From | Greg Kroah-Hartman <> | Subject | [ 88/95] tty: Fix transient pty write() EIO | Date | Tue, 25 Jun 2013 11:33:15 -0700 |
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3.9-stable review patch. If anyone has any objections, please let me know.
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From: Peter Hurley <peter@hurleysoftware.com>
commit 7c61c3d8f44d5d822f758754287af644307b4af9 upstream.
Commit 699390354da6c258b65bf8fa79cfd5feaede50b6 ('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: Markus Trippelsdorf <markus@trippelsdorf.de> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Tested-by: Mikael Pettersson <mikpe@it.uu.se> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/tty/pty.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-)
--- a/drivers/tty/pty.c +++ b/drivers/tty/pty.c @@ -244,14 +244,9 @@ static void pty_flush_buffer(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 *t 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,
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