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=-8.2 required=3.0 tests=BAYES_00,GB_FAKE_RF_SHORT, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,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 606A7C49EA5 for ; Thu, 24 Jun 2021 05:31:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4944E6115A for ; Thu, 24 Jun 2021 05:31:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230270AbhFXFdU (ORCPT ); Thu, 24 Jun 2021 01:33:20 -0400 Received: from out02.mta.xmission.com ([166.70.13.232]:43602 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230093AbhFXFdT (ORCPT ); Thu, 24 Jun 2021 01:33:19 -0400 Received: from in01.mta.xmission.com ([166.70.13.51]) by out02.mta.xmission.com with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1lwHx5-00FHtl-9k; Wed, 23 Jun 2021 23:30:59 -0600 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95]:55232 helo=email.xmission.com) by in01.mta.xmission.com with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1lwHx4-0018Mx-7G; Wed, 23 Jun 2021 23:30:58 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: syzbot Cc: akpm@linux-foundation.org, ast@kernel.org, christian@brauner.io, jnewsome@torproject.org, linux-kernel@vger.kernel.org, minchan@kernel.org, oleg@redhat.com, syzkaller-bugs@googlegroups.com, Ingo Molnar References: <000000000000ef5d1b05c57c2262@google.com> Date: Thu, 24 Jun 2021 00:30:16 -0500 In-Reply-To: <000000000000ef5d1b05c57c2262@google.com> (syzbot's message of "Wed, 23 Jun 2021 22:17:16 -0700") Message-ID: <87fsx7akyf.fsf@disp2133> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1lwHx4-0018Mx-7G;;;mid=<87fsx7akyf.fsf@disp2133>;;;hst=in01.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX1+Z3hExiG9ewRFO3HREZUwvFlw/MIOaijc= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: Re: [syzbot] KASAN: out-of-bounds Read in do_exit X-SA-Exim-Version: 4.2.1 (built Sat, 08 Feb 2020 21:53:50 +0000) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org syzbot writes: > Hello, > > syzbot found the following issue on: This looks like dueling debug mechanism. At a quick glance stack_no_used is deliberately looking for an uninitialized part of the stack. Perhaps the fix is to make KASAN and DEBUG_STACK_USAGE impossible to select at the same time in Kconfig? Eric > > HEAD commit: 9ed13a17 Merge tag 'net-5.13-rc7' of git://git.kernel.org/.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=116c517bd00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=bf635d6d1c7ebabc > dashboard link: https://syzkaller.appspot.com/bug?extid=b80bbdcca4c4dfaa189e > compiler: Debian clang version 11.0.1-2 > > Unfortunately, I don't have any reproducer for this issue yet. > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+b80bbdcca4c4dfaa189e@syzkaller.appspotmail.com > > ================================================================== > BUG: KASAN: out-of-bounds in stack_not_used include/linux/sched/task_stack.h:101 [inline] > BUG: KASAN: out-of-bounds in check_stack_usage kernel/exit.c:711 [inline] > BUG: KASAN: out-of-bounds in do_exit+0x1c6b/0x23d0 kernel/exit.c:869 > Read of size 8 at addr ffffc90017d60400 by task loop0/31717 > > CPU: 0 PID: 31717 Comm: loop0 Not tainted 5.13.0-rc6-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:79 [inline] > dump_stack+0x202/0x31e lib/dump_stack.c:120 > print_address_description+0x5f/0x3b0 mm/kasan/report.c:233 > __kasan_report mm/kasan/report.c:419 [inline] > kasan_report+0x15c/0x200 mm/kasan/report.c:436 > stack_not_used include/linux/sched/task_stack.h:101 [inline] > check_stack_usage kernel/exit.c:711 [inline] > do_exit+0x1c6b/0x23d0 kernel/exit.c:869 > kthread+0x3b8/0x3c0 kernel/kthread.c:315 > ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 > > > Memory state around the buggy address: > ffffc90017d60300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > ffffc90017d60380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >>ffffc90017d60400: 07 07 07 07 07 07 07 07 00 00 00 00 00 00 00 00 > ^ > ffffc90017d60480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > ffffc90017d60500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > ================================================================== > > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@googlegroups.com. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot.