diff options
Diffstat (limited to 'drivers/tty/tty_io.c')
| -rw-r--r-- | drivers/tty/tty_io.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index c05c5af5aa04..35480dd57a30 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -559,6 +559,9 @@ void __tty_hangup(struct tty_struct *tty) tty_lock(); + /* some functions below drop BTM, so we need this bit */ + set_bit(TTY_HUPPING, &tty->flags); + /* inuse_filps is protected by the single tty lock, this really needs to change if we want to flush the workqueue with the lock held */ @@ -578,6 +581,10 @@ void __tty_hangup(struct tty_struct *tty) } spin_unlock(&tty_files_lock); + /* + * it drops BTM and thus races with reopen + * we protect the race by TTY_HUPPING + */ tty_ldisc_hangup(tty); read_lock(&tasklist_lock); @@ -615,7 +622,6 @@ void __tty_hangup(struct tty_struct *tty) tty->session = NULL; tty->pgrp = NULL; tty->ctrl_status = 0; - set_bit(TTY_HUPPED, &tty->flags); spin_unlock_irqrestore(&tty->ctrl_lock, flags); /* Account for the p->signal references we killed */ @@ -641,6 +647,7 @@ void __tty_hangup(struct tty_struct *tty) * can't yet guarantee all that. */ set_bit(TTY_HUPPED, &tty->flags); + clear_bit(TTY_HUPPING, &tty->flags); tty_ldisc_enable(tty); tty_unlock(); @@ -1310,7 +1317,9 @@ static int tty_reopen(struct tty_struct *tty) { struct tty_driver *driver = tty->driver; - if (test_bit(TTY_CLOSING, &tty->flags)) + if (test_bit(TTY_CLOSING, &tty->flags) || + test_bit(TTY_HUPPING, &tty->flags) || + test_bit(TTY_LDISC_CHANGING, &tty->flags)) return -EIO; if (driver->type == TTY_DRIVER_TYPE_PTY && |