From 808ffa3d302257b9dc37b1412c1fcdf976fcddac Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Tue, 27 Jan 2009 11:50:37 +0000 Subject: [PATCH] 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 Signed-off-by: Alan Cox Signed-off-by: Linus Torvalds --- drivers/char/tty_io.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) 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) { -- 2.20.1