From f18f9498e90327b9b0e245e191029e6e1996d203 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Mon, 30 Nov 2009 13:18:35 +0000 Subject: [PATCH] tty: Push the lock down further into the ldisc code Signed-off-by: Alan Cox Signed-off-by: Greg Kroah-Hartman --- drivers/char/tty_io.c | 2 -- drivers/char/tty_ldisc.c | 12 +++++++++--- 2 files changed, 9 insertions(+), 5 deletions(-) diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index 1e241309361..c408c81c06a 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -1347,9 +1347,7 @@ struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx, * If we fail here just call release_tty to clean up. No need * to decrement the use counts, as release_tty doesn't care. */ - lock_kernel(); retval = tty_ldisc_setup(tty, tty->link); - unlock_kernel(); if (retval) goto release_mem_out; return tty; diff --git a/drivers/char/tty_ldisc.c b/drivers/char/tty_ldisc.c index d914e77f7f0..3f653f7d849 100644 --- a/drivers/char/tty_ldisc.c +++ b/drivers/char/tty_ldisc.c @@ -445,8 +445,14 @@ static void tty_set_termios_ldisc(struct tty_struct *tty, int num) 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 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) return 0; } + unlock_kernel(); /* * Problem: What do we do if this blocks ? * We could deadlock here @@ -573,7 +580,6 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) tty_wait_until_sent(tty, 0); - unlock_kernel(); mutex_lock(&tty->ldisc_mutex); /*