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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7A8FBC433EF for ; Mon, 13 Jun 2022 11:09:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351802AbiFMLI1 (ORCPT ); Mon, 13 Jun 2022 07:08:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57592 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351050AbiFMLCx (ORCPT ); Mon, 13 Jun 2022 07:02:53 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BF0B131513; Mon, 13 Jun 2022 03:33:18 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 1AD3FB80EAC; Mon, 13 Jun 2022 10:33:16 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 770C8C34114; Mon, 13 Jun 2022 10:33:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1655116394; bh=1OU0RzNa4702j9LL3ywBApit50031ThIizCQdJtB1AE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=j/X00ejBU8Wx8cqIjiZ7OMjnuLT9pGJxkVS6I/D0UAJBAeAtvCkwEr8bBXKhyHOKl E5bv395lBQWEbcYJYuyokLbe/Yflhu7JXZ8goVuzZDgrzTmVkVEaIr5vrh6imkH/6I rKM26k6kdBa1rwPrHuVohzZxdG+p16VwRkA7rRgc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jiri Slaby , Zheyu Ma , Sasha Levin Subject: [PATCH 4.14 183/218] tty: synclink_gt: Fix null-pointer-dereference in slgt_clean() Date: Mon, 13 Jun 2022 12:10:41 +0200 Message-Id: <20220613094926.160808696@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220613094908.257446132@linuxfoundation.org> References: <20220613094908.257446132@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Zheyu Ma [ Upstream commit 689ca31c542687709ba21ec2195c1fbce34fd029 ] When the driver fails at alloc_hdlcdev(), and then we remove the driver module, we will get the following splat: [ 25.065966] general protection fault, probably for non-canonical address 0xdffffc0000000182: 0000 [#1] PREEMPT SMP KASAN PTI [ 25.066914] KASAN: null-ptr-deref in range [0x0000000000000c10-0x0000000000000c17] [ 25.069262] RIP: 0010:detach_hdlc_protocol+0x2a/0x3e0 [ 25.077709] Call Trace: [ 25.077924] [ 25.078108] unregister_hdlc_device+0x16/0x30 [ 25.078481] slgt_cleanup+0x157/0x9f0 [synclink_gt] Fix this by checking whether the 'info->netdev' is a null pointer first. Reviewed-by: Jiri Slaby Signed-off-by: Zheyu Ma Link: https://lore.kernel.org/r/20220410114814.3920474-1-zheyuma97@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/synclink_gt.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/tty/synclink_gt.c b/drivers/tty/synclink_gt.c index 9d68f89a2bf8..4b5ff6e173bd 100644 --- a/drivers/tty/synclink_gt.c +++ b/drivers/tty/synclink_gt.c @@ -1822,6 +1822,8 @@ static int hdlcdev_init(struct slgt_info *info) */ static void hdlcdev_exit(struct slgt_info *info) { + if (!info->netdev) + return; unregister_hdlc_device(info->netdev); free_netdev(info->netdev); info->netdev = NULL; -- 2.35.1