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,FAKE_REPLY_C,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 8D2E8ECDFB1 for ; Tue, 17 Jul 2018 19:28:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3594F20693 for ; Tue, 17 Jul 2018 19:28:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="D5nOakqx" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3594F20693 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 S1730052AbeGQUCN (ORCPT ); Tue, 17 Jul 2018 16:02:13 -0400 Received: from mail-pl0-f68.google.com ([209.85.160.68]:46148 "EHLO mail-pl0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729737AbeGQUCN (ORCPT ); Tue, 17 Jul 2018 16:02:13 -0400 Received: by mail-pl0-f68.google.com with SMTP id 30-v6so881249pld.13; Tue, 17 Jul 2018 12:28:09 -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:mime-version:content-disposition :in-reply-to:user-agent; bh=1Knnd+V32HjVtLDxmw3Hp1WE5hR4HzI9y9e5WTMUyQg=; b=D5nOakqx1fZZRox3jtqIE5/ycwQAsZowIjRSQMyxPyCCaQS6PL//ozM+xbJMiSiw4C E+W7EelZPhuepYXoWDVN8aMKvCYIisFWX+VHHibYSCCDn4Rq0U6k6OUc/8MgsiVh1Kia SU4jQFPHhOkZ6tG+PykzJBVG9mOE1XchXjl4DqXfap20QN6ltXnALelEY2D6TZKG4zLE 0yNby8IcmUN87rD/MzoJwMnc9gbl2I2oeDn1T+LPchOLBbac5FFo/wzofTWEXHxveyeB FpXdzzQbw2BrNgwpfBIDC14kT/otokf7x9guTrNG/KRStF6QPKc1dBaMVOA6lnJ8uqHo bKaw== 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:mime-version :content-disposition:in-reply-to:user-agent; bh=1Knnd+V32HjVtLDxmw3Hp1WE5hR4HzI9y9e5WTMUyQg=; b=TV2+aoisINigzD93BvBsv4yFbMNNmXnfYt7nNwAWy/XpzATepHMfUbFH4lj1/evFlN XcbxYcZwHJrysH+6pMwTCo24JZ6dbgvqhm6By4U3Q8AmK86vAu8gNPzT/FKEseVJh5m1 wwu3qu2Ad30BJHKnSGJ758VBgMukg/D3nJaM8001Cxo1qWzbWQfFAcRJwSmcO94r+11S XcCsglM/Yc8dIwftF+Si4+qPpjcn1fDnnpVBXXp4yoYccbuMFDzpUCGV3LFIIbXedqPd +2EGB409ccSTrYMEPfhwrXAVLin+62FXcRd5UETK4QYxtxPxaQD3HqwGucMgl2XV+2ek RLZQ== X-Gm-Message-State: AOUpUlGKTdlelIewG8KNPAUTvK0GR5TYeMxKc5y6mm9/kr6aCqR95D6V bIxH1Ut+tzIZeeSHG1gO/GE= X-Google-Smtp-Source: AAOMgpfIM+MPMSl9HJ8uV5iV55nnMhTEAhXanm7BALsQWAC7c3/OLj7fHiNzl+3DrU2/ljbe1j76Pg== X-Received: by 2002:a17:902:22:: with SMTP id 31-v6mr2884773pla.332.1531855688762; Tue, 17 Jul 2018 12:28:08 -0700 (PDT) Received: from gmail.com ([2620:15c:17:3:dc28:5c82:b905:e8a8]) by smtp.gmail.com with ESMTPSA id q5-v6sm2165493pgv.61.2018.07.17.12.28.07 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 17 Jul 2018 12:28:08 -0700 (PDT) Date: Tue, 17 Jul 2018 12:28:06 -0700 From: Eric Biggers To: Mike Rapoport , Andrea Arcangeli Cc: syzbot , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk Subject: Re: kernel BUG at fs/userfaultfd.c:LINE! (2) Message-ID: <20180717192806.GI75957@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <000000000000dcb1a1057112c66a@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 [+Cc userfaultfd developers and linux-mm] The reproducer hits the BUG_ON() in userfaultfd_release(): BUG_ON(!!vma->vm_userfaultfd_ctx.ctx ^ !!(vma->vm_flags & (VM_UFFD_MISSING | VM_UFFD_WP))); On Sun, Jul 15, 2018 at 05:19:03PM -0700, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: 37b5dca2898d Merge tag 'rtc-4.18-2' of git://git.kernel.or.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=12aaf3b2400000 > kernel config: https://syzkaller.appspot.com/x/.config?x=25856fac4e580aa7 > dashboard link: https://syzkaller.appspot.com/bug?extid=121be635a7a35ddb7dcb > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=11176d62400000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1362b368400000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+121be635a7a35ddb7dcb@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) > ------------[ cut here ]------------ > kernel BUG at fs/userfaultfd.c:883! > invalid opcode: 0000 [#1] SMP KASAN > CPU: 0 PID: 4708 Comm: syz-executor086 Not tainted 4.18.0-rc4+ #148 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > RIP: 0010:userfaultfd_release+0x5fb/0x770 fs/userfaultfd.c:882 > Code: 00 31 c0 48 8b 4d d0 65 48 33 0c 25 28 00 00 00 0f 85 a1 00 00 00 48 > 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 75 be a0 ff <0f> 0b 4c 89 f7 e8 > 0b 9e de ff e9 11 fc ff ff 4c 89 e7 e8 5e 9d de > RSP: 0018:ffff8801d8407a80 EFLAGS: 00010293 > RAX: ffff8801d8742080 RBX: dffffc0000000000 RCX: ffffffff81db4a59 > RDX: 0000000000000000 RSI: ffffffff81db4ccb RDI: 0000000000000000 > RBP: ffff8801d8407bd0 R08: ffff8801d8742080 R09: 0000000000000000 > R10: ffff8801d87428b8 R11: 16fb0df9f74494d6 R12: ffff8801d89a3b58 > R13: 0000000000000000 R14: ffff8801d89a3a50 R15: 0000000000000000 > FS: 0000000000ed6880(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f45c6b81e78 CR3: 00000001acb61000 CR4: 00000000001406f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > __fput+0x355/0x8b0 fs/file_table.c:209 > ____fput+0x15/0x20 fs/file_table.c:243 > task_work_run+0x1ec/0x2a0 kernel/task_work.c:113 > tracehook_notify_resume include/linux/tracehook.h:192 [inline] > exit_to_usermode_loop+0x313/0x370 arch/x86/entry/common.c:166 > prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] > syscall_return_slowpath arch/x86/entry/common.c:268 [inline] > do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x405471 > Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 54 17 00 00 c3 48 > 83 ec 08 e8 6a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 > c2 e8 b3 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01 > RSP: 002b:00007ffcad3db600 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 > RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000405471 > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005 > RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 > R10: 00007ffcad3db610 R11: 0000000000000293 R12: 00000000006dbc3c > R13: 00000000006dbda0 R14: 0000000000000008 R15: 0000000000000001 > Modules linked in: > Dumping ftrace buffer: > (ftrace buffer empty) > ---[ end trace 638e68cedadb8eda ]--- > RIP: 0010:userfaultfd_release+0x5fb/0x770 fs/userfaultfd.c:882 > Code: 00 31 c0 48 8b 4d d0 65 48 33 0c 25 28 00 00 00 0f 85 a1 00 00 00 48 > 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 75 be a0 ff <0f> 0b 4c 89 f7 e8 > 0b 9e de ff e9 11 fc ff ff 4c 89 e7 e8 5e 9d de > RSP: 0018:ffff8801d8407a80 EFLAGS: 00010293 > RAX: ffff8801d8742080 RBX: dffffc0000000000 RCX: ffffffff81db4a59 > RDX: 0000000000000000 RSI: ffffffff81db4ccb RDI: 0000000000000000 > RBP: ffff8801d8407bd0 R08: ffff8801d8742080 R09: 0000000000000000 > R10: ffff8801d87428b8 R11: 16fb0df9f74494d6 R12: ffff8801d89a3b58 > R13: 0000000000000000 R14: ffff8801d89a3a50 R15: 0000000000000000 > FS: 0000000000ed6880(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f45c6b81e78 CR3: 00000001acb61000 CR4: 00000000001406f0 > 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/000000000000dcb1a1057112c66a%40google.com. > For more options, visit https://groups.google.com/d/optout.