tty: Push the lock down further into the ldisc code
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/char/tty_ldisc.c b/drivers/char/tty_ldisc.c
index d914e77..3f653f7 100644
--- a/drivers/char/tty_ldisc.c
+++ b/drivers/char/tty_ldisc.c
@@ -445,8 +445,14 @@
static int tty_ldisc_open(struct tty_struct *tty, struct tty_ldisc *ld)
{
WARN_ON(test_and_set_bit(TTY_LDISC_OPEN, &tty->flags));
- if (ld->ops->open)
- return ld->ops->open(tty);
+ if (ld->ops->open) {
+ int ret;
+ /* BKL here locks verus a hangup event */
+ lock_kernel();
+ ret = ld->ops->open(tty);
+ unlock_kernel();
+ return ret;
+ }
return 0;
}
@@ -566,6 +572,7 @@
return 0;
}
+ unlock_kernel();
/*
* Problem: What do we do if this blocks ?
* We could deadlock here
@@ -573,7 +580,6 @@
tty_wait_until_sent(tty, 0);
- unlock_kernel();
mutex_lock(&tty->ldisc_mutex);
/*