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=-10.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,NICE_REPLY_A,SPF_HELO_NONE,URIBL_BLOCKED, USER_AGENT_SANE_1 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 68127C47066 for ; Thu, 1 Apr 2021 17:45:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9ABAE61277 for ; Thu, 1 Apr 2021 17:45:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236270AbhDARoQ (ORCPT ); Thu, 1 Apr 2021 13:44:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57186 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234591AbhDARiP (ORCPT ); Thu, 1 Apr 2021 13:38:15 -0400 Received: from mail-io1-xd2d.google.com (mail-io1-xd2d.google.com [IPv6:2607:f8b0:4864:20::d2d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8151BC02FEA3 for ; Thu, 1 Apr 2021 09:09:20 -0700 (PDT) Received: by mail-io1-xd2d.google.com with SMTP id n198so501021iod.0 for ; Thu, 01 Apr 2021 09:09:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=48dyaiUyVqMwLE0OwYdfA5ySCjDx5Xf12eY4xzzdxXs=; b=Q/SR523Ar1LWM4oiRWdcYVGDmBiu+zeFT7gA4UE9r2y+wh90OYXx0JJGDPcwMu5adH uaxbD0Pu9f5900tZeP3hEe5v2db7lKqxdaDTGAE/r7ppii0REDgnpsq6WNA0PbdjmASs de+PdzOIIxIaRBSOh6zS9hLprKOaCN962rHWHBbcMLKOPqJaWZnw7i9AAS1x73820wX4 8sdjPlS3OXDG74thkV/VB4/we1prlMFDH0VAhEh7RXO01Mzf/ywd8gl8j+WVw6mGPw+B rI1wrqE5kG1B24gee8UOlunMIzDWGoXzeN2be49I1Kr/MgV80/4Up2UOB+FRq0EsQwSm ieQA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=48dyaiUyVqMwLE0OwYdfA5ySCjDx5Xf12eY4xzzdxXs=; b=ptTndcpNSw2KvSbiv7vJ1mgpp3Vle9953ekZYzOB8Y/tZGDx31TeUEG7ezNFkjkf/B Y0hbRQNL91MFvsPoZx2s9SOcLVFVyIYMJRVM+YQTI3U2iw6dLDJyaPijgRUPi4qqeWv6 AxUyS6UZxbKSiAGDwxeIyuzxKnFIHJKVo/5hGRXhMgWJ7bvvOlq2ldeGlN/Qzz82ZXiS tYI9GGV2ZtUqZUpxeFEuaoWH1e0FSUAQtmDAdJW0f8G10eRip9x6eeHJx1E197fcXS3R 2OtJV7D9MvqUB46LrzBDe0X0XXQNSTzi61wuvCJpnHG1wo72LVP5foTE6UjIPgGDgSJ2 2UmA== X-Gm-Message-State: AOAM533jeuEg33MSsC/CytK3SzT4iSFxY9aJG0mfLi/4hEZyWpbv2RhA osIpd90GW3pTMG2Cg1bmSFV1eMLdPKd6Zw== X-Google-Smtp-Source: ABdhPJx71PWvRQl21JSc09Uw5jU8+9y4mYpLpsKeo9v5KDSxkuD5Ozc7hcvTXmb/nzJ5eqed0eNeZw== X-Received: by 2002:a5e:c102:: with SMTP id v2mr7178492iol.137.1617293359632; Thu, 01 Apr 2021 09:09:19 -0700 (PDT) Received: from [192.168.1.30] ([65.144.74.34]) by smtp.gmail.com with ESMTPSA id b4sm2637045ilj.11.2021.04.01.09.09.19 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 01 Apr 2021 09:09:19 -0700 (PDT) Subject: Re: [syzbot] WARNING in mntput_no_expire (2) To: Christian Brauner , syzbot Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk, io-uring@vger.kernel.org References: <0000000000003a565e05bee596f2@google.com> <20210401154515.k24qdd2lzhtneu47@wittgenstein> From: Jens Axboe Message-ID: <90e7e339-eaec-adb2-cfed-6dc058a117a3@kernel.dk> Date: Thu, 1 Apr 2021 10:09:18 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210401154515.k24qdd2lzhtneu47@wittgenstein> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 4/1/21 9:45 AM, Christian Brauner wrote: > On Thu, Apr 01, 2021 at 02:09:20AM -0700, syzbot wrote: >> Hello, >> >> syzbot found the following issue on: >> >> HEAD commit: d19cc4bf Merge tag 'trace-v5.12-rc5' of git://git.kernel.o.. >> git tree: upstream >> console output: https://syzkaller.appspot.com/x/log.txt?x=1018f281d00000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=d1a3d65a48dbd1bc >> dashboard link: https://syzkaller.appspot.com/bug?extid=c88a7030da47945a3cc3 >> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12f50d11d00000 >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=137694a1d00000 >> >> IMPORTANT: if you fix the issue, please add the following tag to the commit: >> Reported-by: syzbot+c88a7030da47945a3cc3@syzkaller.appspotmail.com >> >> ------------[ cut here ]------------ >> WARNING: CPU: 1 PID: 8409 at fs/namespace.c:1186 mntput_no_expire+0xaca/0xcb0 fs/namespace.c:1186 >> Modules linked in: >> CPU: 1 PID: 8409 Comm: syz-executor035 Not tainted 5.12.0-rc5-syzkaller #0 >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 >> RIP: 0010:mntput_no_expire+0xaca/0xcb0 fs/namespace.c:1186 >> Code: ff 48 c7 c2 e0 cb 78 89 be c2 02 00 00 48 c7 c7 a0 cb 78 89 c6 05 e5 6d e5 0b 01 e8 ff e1 f6 06 e9 3f fd ff ff e8 c6 a5 a8 ff <0f> 0b e9 fc fc ff ff e8 ba a5 a8 ff e8 55 dc 94 ff 31 ff 89 c5 89 >> RSP: 0018:ffffc9000165fc78 EFLAGS: 00010293 >> RAX: 0000000000000000 RBX: 1ffff920002cbf95 RCX: 0000000000000000 >> RDX: ffff88802072d4c0 RSI: ffffffff81cb4b8a RDI: 0000000000000003 >> RBP: ffff888011656900 R08: 0000000000000000 R09: ffffffff8fa978af >> R10: ffffffff81cb4884 R11: 0000000000000000 R12: 0000000000000008 >> R13: ffffc9000165fcc8 R14: dffffc0000000000 R15: 00000000ffffffff >> FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> CR2: 000055a722053160 CR3: 000000000bc8e000 CR4: 00000000001506e0 >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >> Call Trace: >> mntput fs/namespace.c:1232 [inline] >> cleanup_mnt+0x523/0x530 fs/namespace.c:1132 >> task_work_run+0xdd/0x1a0 kernel/task_work.c:140 >> exit_task_work include/linux/task_work.h:30 [inline] >> do_exit+0xbfc/0x2a60 kernel/exit.c:825 >> do_group_exit+0x125/0x310 kernel/exit.c:922 >> __do_sys_exit_group kernel/exit.c:933 [inline] >> __se_sys_exit_group kernel/exit.c:931 [inline] >> __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:931 >> do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 >> entry_SYSCALL_64_after_hwframe+0x44/0xae >> RIP: 0033:0x446af9 >> Code: Unable to access opcode bytes at RIP 0x446acf. >> RSP: 002b:00000000005dfe48 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 >> RAX: ffffffffffffffda RBX: 00000000004ce450 RCX: 0000000000446af9 >> RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000001 >> RBP: 0000000000000001 R08: ffffffffffffffbc R09: 0000000000000000 >> R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004ce450 >> R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001 > > [+Cc Jens + io_uring] > > Hm, this reproducer uses io_uring and it's the io_uring_enter() that > triggers this reliably. With this reproducer I've managed to reproduce > the issue on v5.12-rc4, and v5.12-rc3, v5.12-rc2 and v5.12-rc1. > It's not reproducible at > 9820b4dca0f9c6b7ab8b4307286cdace171b724d > which is the commit immediately before the first v5.12 io_uring merge. > It's first reproducible with the first io_uring merge for v5.12, i.e. > 5bbb336ba75d95611a7b9456355b48705016bdb1 Thanks, that's good info. I'll take a look at it and see if I can reproduce. -- Jens Axboe