From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1775CC7112B for ; Sun, 14 Oct 2018 15:48:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D799320876 for ; Sun, 14 Oct 2018 15:48:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D799320876 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=decadent.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729723AbeJNX3Z (ORCPT ); Sun, 14 Oct 2018 19:29:25 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:37308 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728125AbeJNX3Y (ORCPT ); Sun, 14 Oct 2018 19:29:24 -0400 Received: from [2a02:8011:400e:2:cbab:f00:c93f:614] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1gBiLx-0004cf-C8; Sun, 14 Oct 2018 16:30:49 +0100 Received: from ben by deadeye with local (Exim 4.91) (envelope-from ) id 1gBiLU-0000PN-Pl; Sun, 14 Oct 2018 16:30:20 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Greg Kroah-Hartman" , "Tetsuo Handa" , "Jiri Slaby" , "syzbot" Date: Sun, 14 Oct 2018 16:25:41 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 197/366] tty: Don't call panic() at tty_ldisc_init() In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:cbab:f00:c93f:614 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.60-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Tetsuo Handa commit 903f9db10f18f735e62ba447147b6c434b6af003 upstream. 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 Reported-by: syzbot Cc: Greg Kroah-Hartman Cc: Jiri Slaby Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- drivers/tty/tty_io.c | 5 ++++- drivers/tty/tty_ldisc.c | 5 +++-- include/linux/tty.h | 2 +- 3 files changed, 8 insertions(+), 4 deletions(-) --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -3036,7 +3036,10 @@ struct tty_struct *alloc_tty_struct(stru 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); --- a/drivers/tty/tty_ldisc.c +++ b/drivers/tty/tty_ldisc.c @@ -820,12 +820,13 @@ void tty_ldisc_release(struct tty_struct * 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; } /** --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -556,7 +556,7 @@ extern int tty_unregister_ldisc(int disc extern int tty_set_ldisc(struct tty_struct *tty, int ldisc); extern int tty_ldisc_setup(struct tty_struct *tty, struct tty_struct *o_tty); extern void tty_ldisc_release(struct tty_struct *tty, struct tty_struct *o_tty); -extern void tty_ldisc_init(struct tty_struct *tty); +extern int __must_check tty_ldisc_init(struct tty_struct *tty); extern void tty_ldisc_deinit(struct tty_struct *tty); extern void tty_ldisc_begin(void);