tty: Don't call panic() at tty_ldisc_init()
syzbot is reporting kernel panic [1] triggered by memory allocation failure
at tty_ldisc_get() from tty_ldisc_init(). But since both tty_ldisc_get()
and caller of tty_ldisc_init() can cleanly handle errors, tty_ldisc_init()
does not need to call panic() when tty_ldisc_get() failed.
[1] https://syzkaller.appspot.com/bug?id=883431818e036ae6a9981156a64b821110f39187
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 63114ea..7c838b9 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2816,7 +2816,10 @@ struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
kref_init(&tty->kref);
tty->magic = TTY_MAGIC;
- tty_ldisc_init(tty);
+ if (tty_ldisc_init(tty)) {
+ kfree(tty);
+ return NULL;
+ }
tty->session = NULL;
tty->pgrp = NULL;
mutex_init(&tty->legacy_mutex);
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
index c1cf6cb83..8a88a77 100644
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/tty_ldisc.c
@@ -821,12 +821,13 @@ EXPORT_SYMBOL_GPL(tty_ldisc_release);
* the tty structure is not completely set up when this call is made.
*/
-void tty_ldisc_init(struct tty_struct *tty)
+int tty_ldisc_init(struct tty_struct *tty)
{
struct tty_ldisc *ld = tty_ldisc_get(tty, N_TTY);
if (IS_ERR(ld))
- panic("n_tty: init_tty");
+ return PTR_ERR(ld);
tty->ldisc = ld;
+ return 0;
}
/**