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pty: Ignore slave pty close() if never successfully opened

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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>
This commit is contained in:
Peter Hurley 2013-01-30 12:43:50 -05:00 committed by Greg Kroah-Hartman
parent 7acf6cd80b
commit 699390354d
1 changed files with 6 additions and 0 deletions
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6
drivers/tty/pty.c
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@ -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;