From 36697529b5bbe36911e39a6309e7a7c9250d280a Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sat, 15 Jun 2013 07:04:48 -0400 Subject: tty: Replace ldisc locking with ldisc_sem Line discipline locking was performed with a combination of a mutex, a status bit, a count, and a waitqueue -- basically, a rw semaphore. Replace the existing combination with an ld_semaphore. Fixes: 1) the 'reference acquire after ldisc locked' bug 2) the over-complicated halt mechanism 3) lock order wrt. tty_lock() 4) dropping locks while changing ldisc 5) previously unidentified deadlock while locking ldisc from both linked ttys concurrently 6) previously unidentified recursive deadlocks Adds much-needed lockdep diagnostics. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- include/linux/tty_ldisc.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'include/linux/tty_ldisc.h') diff --git a/include/linux/tty_ldisc.h b/include/linux/tty_ldisc.h index a1b04899982..23bdd9debb8 100644 --- a/include/linux/tty_ldisc.h +++ b/include/linux/tty_ldisc.h @@ -203,8 +203,7 @@ struct tty_ldisc_ops { struct tty_ldisc { struct tty_ldisc_ops *ops; - atomic_t users; - wait_queue_head_t wq_idle; + struct tty_struct *tty; }; #define TTY_LDISC_MAGIC 0x5403 -- cgit v1.2.3-70-g09d2