tty: Fix BKL taken under a spinlock bug introduced in the BKL split

The fasync path takes the BKL (it probably doesn't need to in fact) while holding the file_list spinlock. You can't do that with the kernel lock: it causes lock inversions and deadlocks. Leave the BKL over that bit for the moment. Identified by AKPM. Signed-off-by: Alan Cox <[email protected]> Acked-and-Tested-by: Thomas Gleixner <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
ambv · Dec 12, 2009 · 6698e34 · 6698e34
1 parent 09cea96
commit 6698e34
Showing 1 changed file with 0 additions and 2 deletions.
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
@@ -516,7 +516,6 @@ static void do_tty_hangup(struct work_struct *work)
 	/* inuse_filps is protected by the single kernel lock */
 	lock_kernel();
 	check_tty_count(tty, "do_tty_hangup");
-	unlock_kernel();
 
 	file_list_lock();
 	/* This breaks for file handles being sent over AF_UNIX sockets ? */
@@ -531,7 +530,6 @@ static void do_tty_hangup(struct work_struct *work)
 	}
 	file_list_unlock();
 
-	lock_kernel();
 	tty_ldisc_hangup(tty);
 
 	read_lock(&tasklist_lock);