tty_open can return to userspace holding tty_mutex

__tty_open could return (to userspace) holding the tty_mutex thanks to a
regression introduced by 4a2b5fddd5 ("Move
tty lookup/reopen to caller").

This was found by bisecting an fsfuzzer problem.  Admittedly I have no
idea how it managed to tickle this 100% reliably, but it is clearly a
regression and when hit leaves the box in a completely unusable state.
This patch lets the fsfuzzer test complete every time.

Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Eric Paris 2009-01-27 11:50:37 +00:00 committed by Linus Torvalds
parent 5ee8100721
commit 808ffa3d30

View file

@ -1817,8 +1817,10 @@ static int __tty_open(struct inode *inode, struct file *filp)
/* check whether we're reopening an existing tty */
tty = tty_driver_lookup_tty(driver, inode, index);
if (IS_ERR(tty))
if (IS_ERR(tty)) {
mutex_unlock(&tty_mutex);
return PTR_ERR(tty);
}
}
if (tty) {