diff options
| author | Peter Hurley <peter@hurleysoftware.com> | 2016-01-10 22:41:02 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-01-27 15:01:44 -0800 |
| commit | a570a49abd343102ce681bbf8273897c3c9fd2d1 (patch) | |
| tree | ae0fb349f31a88ab6074bdf9c791a03680697bdf /drivers/tty/tty_ldisc.c | |
| parent | e55afd11a48354c810caf6b6ad4c103016a88230 (diff) | |
tty: Handle NULL tty->ldisc
In preparation of destroying line discipline on hangup, fix
ldisc core operations to properly handle when the tty's ldisc is
NULL.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/tty_ldisc.c')
| -rw-r--r-- | drivers/tty/tty_ldisc.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c index d6805e1aee59..982af70c95ce 100644 --- a/drivers/tty/tty_ldisc.c +++ b/drivers/tty/tty_ldisc.c @@ -269,7 +269,8 @@ const struct file_operations tty_ldiscs_proc_fops = { struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *tty) { ldsem_down_read(&tty->ldisc_sem, MAX_SCHEDULE_TIMEOUT); - WARN_ON(!tty->ldisc); + if (!tty->ldisc) + ldsem_up_read(&tty->ldisc_sem); return tty->ldisc; } EXPORT_SYMBOL_GPL(tty_ldisc_ref_wait); @@ -460,7 +461,7 @@ static int tty_ldisc_open(struct tty_struct *tty, struct tty_ldisc *ld) if (ret) clear_bit(TTY_LDISC_OPEN, &tty->flags); - tty_ldisc_debug(tty, "%p: opened\n", tty->ldisc); + tty_ldisc_debug(tty, "%p: opened\n", ld); return ret; } return 0; @@ -481,7 +482,7 @@ static void tty_ldisc_close(struct tty_struct *tty, struct tty_ldisc *ld) clear_bit(TTY_LDISC_OPEN, &tty->flags); if (ld->ops->close) ld->ops->close(tty); - tty_ldisc_debug(tty, "%p: closed\n", tty->ldisc); + tty_ldisc_debug(tty, "%p: closed\n", ld); } /** @@ -544,6 +545,11 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) if (retval) goto err; + if (!tty->ldisc) { + retval = -EIO; + goto out; + } + /* Check the no-op case */ if (tty->ldisc->ops->num == ldisc) goto out; @@ -659,7 +665,7 @@ void tty_ldisc_hangup(struct tty_struct *tty) int reset = tty->driver->flags & TTY_DRIVER_RESET_TERMIOS; int err = 0; - tty_ldisc_debug(tty, "%p: closing\n", tty->ldisc); + tty_ldisc_debug(tty, "%p: hangup\n", tty->ldisc); ld = tty_ldisc_ref(tty); if (ld != NULL) { @@ -743,6 +749,8 @@ int tty_ldisc_setup(struct tty_struct *tty, struct tty_struct *o_tty) static void tty_ldisc_kill(struct tty_struct *tty) { + if (!tty->ldisc) + return; /* * Now kill off the ldisc */ |