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=1.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,FSL_HELO_FAKE, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT autolearn=no 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 2308AECDFB3 for ; Tue, 17 Jul 2018 18:52:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CDD7820837 for ; Tue, 17 Jul 2018 18:52:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="CUzYCj8s" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CDD7820837 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com 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 S1730813AbeGQT0X (ORCPT ); Tue, 17 Jul 2018 15:26:23 -0400 Received: from mail-pf0-f193.google.com ([209.85.192.193]:36570 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729708AbeGQT0X (ORCPT ); Tue, 17 Jul 2018 15:26:23 -0400 Received: by mail-pf0-f193.google.com with SMTP id d14-v6so945300pfo.3; Tue, 17 Jul 2018 11:52:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=ZBQKG7y0QZv1D5wg/6a3pnMTKqdS/yHqhmFErUMCsug=; b=CUzYCj8sKc3WswM0q7HM8C6i/JX/3GZqbdFrC2VbH2T5dkx/uYLTbEwic/v4QoPVtx z+SiBMdY/YwrzrjuOeLmgD25V4sb1e/ESNU/BZQgk2QOxehE4p6VUll273Ei72EK8uz2 hAdeCf2JI3kAmReqA49qd3rSQSuvPXTATNy7xvdE/ogmEvoqVjPYM1KauvqpE9Ed/AgS 2PUigjRSu9oMAkd3JfvxqBaF3rD0+bEWh1a0WSPTcZ/JkR5SiGDhsxvbWOfAxG96wDS1 BPFRPqiLTsNFDYbHK2OIxvofgEHxeBaaYvEgsmV58SsAHfMj7chtGD0o6V99X5uf5KrE Asfw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=ZBQKG7y0QZv1D5wg/6a3pnMTKqdS/yHqhmFErUMCsug=; b=ksLbO/l8eK0HOJeGOhNcxctdSNr4mb21kVCxHVJp2wOHdqtZcuOazAq51dxKEd4W73 G9wJCRFpGoyt0AHVIMp5P2vJq9o4fA8F0t9/nyJk+w/6okEnr3N+Uvbva2ztfhcqvjxp imK2uCwZhzy0qvEzDZjgm1Tc8k9qwGTTyT0Ka4+mbBjC8cLQVwrVWKcboZKx5VxkUARs FMU0UdE69MyIB+QDwStpnrSn2K/cXSuIhdeDJ25VuKYwq9r6pgkatPn7dXr03c+66BYc DZZPprbnNm/hNtPl5X8O0HUKum5dYvh/nkhMZ9PjvVL+/7McXmsrJtHt9mtnmBAoJ4cN M6yg== X-Gm-Message-State: AOUpUlHAuvP4tetD9ebj/1hJVOZ6qenWyhmAY8cVFIGnCdm10aYZ1wGF T92nz6WClPRUZ1HA3qSY/8s= X-Google-Smtp-Source: AAOMgpebYMegFPIBg9YKN2Y8inxNbCFsglA1VgIXeE4DzRRts/Bc4ej+zd72emmCQ98px9Z2ayXNtQ== X-Received: by 2002:a62:90d4:: with SMTP id q81-v6mr1885022pfk.37.1531853544782; Tue, 17 Jul 2018 11:52:24 -0700 (PDT) Received: from gmail.com ([2620:15c:17:3:dc28:5c82:b905:e8a8]) by smtp.gmail.com with ESMTPSA id x2-v6sm7085386pfi.166.2018.07.17.11.52.23 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 17 Jul 2018 11:52:24 -0700 (PDT) Date: Tue, 17 Jul 2018 11:52:22 -0700 From: Eric Biggers To: David Howells Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk, syzbot Subject: Re: general protection fault in do_remount_sb Message-ID: <20180717185222.GF75957@gmail.com> References: <000000000000b2425905705c540f@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <000000000000b2425905705c540f@google.com> User-Agent: Mutt/1.10+35 (c786a508) (2018-06-22) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi David, this looks like another bug in the fs_context patchset. do_remount_sb() is dereferencing a NULL fs_context. On Fri, Jul 06, 2018 at 03:39:03PM -0700, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: 526674536360 Add linux-next specific files for 20180706 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=1642b734400000 > kernel config: https://syzkaller.appspot.com/x/.config?x=c8d1cfc0cb798e48 > dashboard link: https://syzkaller.appspot.com/bug?extid=049ea4b3691673030783 > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=118bf170400000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1783690c400000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+049ea4b3691673030783@syzkaller.appspotmail.com > > random: sshd: uninitialized urandom read (32 bytes read) > random: sshd: uninitialized urandom read (32 bytes read) > random: sshd: uninitialized urandom read (32 bytes read) > kasan: CONFIG_KASAN_INLINE enabled > kasan: GPF could be caused by NULL-ptr deref or user memory access > general protection fault: 0000 [#1] SMP KASAN > CPU: 1 PID: 4462 Comm: syz-executor233 Not tainted 4.18.0-rc3-next-20180706+ > #1 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > RIP: 0010:do_remount_sb+0x371/0x850 fs/super.c:992 > Code: ff ff ff e8 01 85 fa 05 41 89 c5 48 8b 85 30 ff ff ff 48 8d b8 e0 00 > 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 > 74 08 3c 03 0f 8e b5 03 00 00 48 8b 85 30 ff ff > RSP: 0018:ffff8801ac117a38 EFLAGS: 00010202 > RAX: dffffc0000000000 RBX: ffff8801caf68e40 RCX: ffffffff81c5edb2 > RDX: 000000000000001c RSI: ffffffff81edb5ef RDI: 00000000000000e0 > RBP: ffff8801ac117b40 R08: ffff8801ac1e2140 R09: fffffbfff11c24e5 > R10: fffffbfff11c24e5 R11: ffffffff88e1272b R12: ffff8801ac117b18 > R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000 > FS: 0000000001440880(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000020000680 CR3: 00000001ac28f000 CR4: 00000000001406e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > do_umount fs/namespace.c:1467 [inline] > ksys_umount+0xfa7/0x12f0 fs/namespace.c:1585 > __do_sys_umount fs/namespace.c:1596 [inline] > __se_sys_umount fs/namespace.c:1594 [inline] > __x64_sys_umount+0x54/0x80 fs/namespace.c:1594 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x440069 > Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 > 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff > 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007ffded829168 EFLAGS: 00000217 ORIG_RAX: 00000000000000a6 > RAX: ffffffffffffffda RBX: 0030656c69662f2e RCX: 0000000000440069 > RDX: 0000000000440069 RSI: 0000000000000000 RDI: 0000000020000040 > RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 > R10: 00000000004002c8 R11: 0000000000000217 R12: 00000000004018f0 > R13: 0000000000401980 R14: 0000000000000000 R15: 0000000000000000 > Modules linked in: > Dumping ftrace buffer: > (ftrace buffer empty) > ---[ end trace e836fc74e88778be ]--- > RIP: 0010:do_remount_sb+0x371/0x850 fs/super.c:992 > Code: ff ff ff e8 01 85 fa 05 41 89 c5 48 8b 85 30 ff ff ff 48 8d b8 e0 00 > 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 > 74 08 3c 03 0f 8e b5 03 00 00 48 8b 85 30 ff ff > RSP: 0018:ffff8801ac117a38 EFLAGS: 00010202 > RAX: dffffc0000000000 RBX: ffff8801caf68e40 RCX: ffffffff81c5edb2 > RDX: 000000000000001c RSI: ffffffff81edb5ef RDI: 00000000000000e0 > RBP: ffff8801ac117b40 R08: ffff8801ac1e2140 R09: fffffbfff11c24e5 > R10: fffffbfff11c24e5 R11: ffffffff88e1272b R12: ffff8801ac117b18 > R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000 > FS: 0000000001440880(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000020000680 CR3: 00000001ac28f000 CR4: 00000000001406e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > > --- > This bug 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 bug report. See: > https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with > syzbot. > syzbot can test patches for this bug, for details see: > https://goo.gl/tpsmEJ#testing-patches > > -- > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/000000000000b2425905705c540f%40google.com. > For more options, visit https://groups.google.com/d/optout.