From 808ffa3d302257b9dc37b1412c1fcdf976fcddac Mon Sep 17 00:00:00 2001
From: Eric Paris <eparis@redhat.com>
Date: Tue, 27 Jan 2009 11:50:37 +0000
Subject: 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 4a2b5fddd53b80efcb3266ee36e23b8de28e761a ("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>
---
drivers/char/tty_io.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
(limited to 'drivers/char/tty_io.c')
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index d33e5ab06177..bc84e125c6bc 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -1817,8 +1817,10 @@ got_driver:
/* 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) {
--
cgit