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=-2.1 required=3.0 tests=FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 DD6DEFC6194 for ; Fri, 8 Nov 2019 06:05:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B402E214DB for ; Fri, 8 Nov 2019 06:05:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727167AbfKHGF5 (ORCPT ); Fri, 8 Nov 2019 01:05:57 -0500 Received: from mx-out.tlen.pl ([193.222.135.148]:5331 "EHLO mx-out.tlen.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725877AbfKHGF5 (ORCPT ); Fri, 8 Nov 2019 01:05:57 -0500 Received: (wp-smtpd smtp.tlen.pl 29828 invoked from network); 8 Nov 2019 07:05:50 +0100 Received: from unknown (HELO [172.20.2.55]) (p.sarna@o2.pl@[50.233.106.125]) (envelope-sender ) by smtp.tlen.pl (WP-SMTPD) with ECDHE-RSA-AES256-GCM-SHA384 encrypted SMTP for ; 8 Nov 2019 07:05:50 +0100 Subject: Re: BUG: Dentry still in use [unmount of hugetlbfs hugetlbfs] (2) To: syzbot , akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, mhocko@kernel.org, mike.kravetz@oracle.com, sfr@canb.auug.org.au, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk References: <000000000000c620080596cefdf0@google.com> From: Piotr Sarna Message-ID: Date: Fri, 8 Nov 2019 07:05:41 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.0 MIME-Version: 1.0 In-Reply-To: <000000000000c620080596cefdf0@google.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-WP-MailID: 5cbcd82bbaeada83d5d08a62158d2ad0 X-WP-AV: skaner antywirusowy Poczty o2 X-WP-SPAM: NO 0000005 [UTa1] Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org The obvious culprit seems to be the unnecessary call to d_get() when creating a tmp file with tmpfile() call, which is then never countered by dput()... sloppy of me.  I don't know what the procedure is now, but I hope that my patch is simply dequeued from /next. I'll provide a fixed and retested version once I'm back from a conference. On 11/8/19 6:24 AM, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit:    c68c5373 Add linux-next specific files for 20191107 > git tree:       linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=13f62294e00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=742545dcdea21726 > dashboard link: > https://syzkaller.appspot.com/bug?extid=136d2439a4e6561ea00c > compiler:       gcc (GCC) 9.0.0 20181231 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12ed5264e00000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15fe2a64e00000 > > The bug was bisected to: > > commit efe323d5cfecd2ad9dd4aa485e05312f0fa7617a > Author: Piotr Sarna > Date:   Wed Nov 6 05:06:34 2019 +0000 > >     hugetlbfs: add O_TMPFILE support > > bisection log: > https://syzkaller.appspot.com/x/bisect.txt?x=14ac944ae00000 > final crash: https://syzkaller.appspot.com/x/report.txt?x=16ac944ae00000 > console output: https://syzkaller.appspot.com/x/log.txt?x=12ac944ae00000 > > IMPORTANT: if you fix the bug, please add the following tag to the > commit: > Reported-by: syzbot+136d2439a4e6561ea00c@syzkaller.appspotmail.com > Fixes: efe323d5cfec ("hugetlbfs: add O_TMPFILE support") > > BUG: Dentry 00000000c225b886{i=685d,n=#26717}  still in use (1) > [unmount of hugetlbfs hugetlbfs] > ------------[ cut here ]------------ > WARNING: CPU: 1 PID: 8874 at fs/dcache.c:1595 umount_check > fs/dcache.c:1586 [inline] > WARNING: CPU: 1 PID: 8874 at fs/dcache.c:1595 > umount_check.cold+0xe9/0x10a fs/dcache.c:1576 > Kernel panic - not syncing: panic_on_warn set ... > CPU: 1 PID: 8874 Comm: syz-executor027 Not tainted > 5.4.0-rc6-next-20191107 #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, > BIOS Google 01/01/2011 > Call Trace: >  __dump_stack lib/dump_stack.c:77 [inline] >  dump_stack+0x197/0x210 lib/dump_stack.c:118 >  panic+0x2e3/0x75c kernel/panic.c:221 >  __warn.cold+0x2f/0x35 kernel/panic.c:582 >  report_bug+0x289/0x300 lib/bug.c:195 >  fixup_bug arch/x86/kernel/traps.c:174 [inline] >  fixup_bug arch/x86/kernel/traps.c:169 [inline] >  do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:267 >  do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:286 >  invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027 > RIP: 0010:umount_check fs/dcache.c:1595 [inline] > RIP: 0010:umount_check.cold+0xe9/0x10a fs/dcache.c:1576 > Code: 89 ff e8 70 8f ef ff 48 81 c3 88 06 00 00 45 89 e8 4c 89 e1 53 > 4d 8b 0f 4c 89 f2 4c 89 e6 48 c7 c7 20 d9 b6 87 e8 b1 f4 9c ff <0f> 0b > 58 e9 7d 1b ff ff e8 40 8f ef ff e9 29 ff ff ff 45 31 f6 e9 > RSP: 0018:ffff888095c0fbc8 EFLAGS: 00010282 > RAX: 0000000000000060 RBX: ffff888098736688 RCX: 0000000000000000 > RDX: 0000000000000000 RSI: ffffffff815d0b86 RDI: ffffed1012b81f6b > RBP: ffff888095c0fbf8 R08: 0000000000000060 R09: ffffed1015d26161 > R10: ffffed1015d26160 R11: ffff8880ae930b07 R12: ffff888090c7b300 > R13: 0000000000000001 R14: 000000000000685d R15: ffffffff8910a5e0 >  d_walk+0x27e/0x930 fs/dcache.c:1305 >  do_one_tree+0x28/0x40 fs/dcache.c:1602 >  shrink_dcache_for_umount+0x72/0x170 fs/dcache.c:1618 >  generic_shutdown_super+0x6d/0x370 fs/super.c:447 >  kill_anon_super+0x3e/0x60 fs/super.c:1106 >  kill_litter_super+0x50/0x60 fs/super.c:1115 >  deactivate_locked_super+0x95/0x100 fs/super.c:335 >  deactivate_super fs/super.c:366 [inline] >  deactivate_super+0x1b2/0x1d0 fs/super.c:362 >  cleanup_mnt+0x351/0x4c0 fs/namespace.c:1102 >  __cleanup_mnt+0x16/0x20 fs/namespace.c:1109 >  task_work_run+0x145/0x1c0 kernel/task_work.c:113 >  tracehook_notify_resume include/linux/tracehook.h:188 [inline] >  exit_to_usermode_loop+0x316/0x380 arch/x86/entry/common.c:163 >  prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline] >  syscall_return_slowpath arch/x86/entry/common.c:274 [inline] >  do_syscall_64+0x65f/0x760 arch/x86/entry/common.c:300 >  entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x449707 > Code: 44 00 00 b8 08 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 ed dc fb > ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 a6 00 00 00 0f 05 <48> 3d > 01 f0 ff ff 0f 83 cd dc fb ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007ffe00511778 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6 > RAX: 0000000000000000 RBX: 00000000000108a6 RCX: 0000000000449707 > RDX: 0000000000400df0 RSI: 0000000000000002 RDI: 00007ffe00511820 > RBP: 00000000000022cb R08: 0000000000000000 R09: 0000000000000009 > R10: 0000000000000005 R11: 0000000000000202 R12: 00007ffe005128d0 > R13: 0000000002133880 R14: 0000000000000000 R15: 0000000000000000 > Kernel Offset: disabled > Rebooting in 86400 seconds.. > > > --- > 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#status for how to communicate with syzbot. > For information about bisection process see: > https://goo.gl/tpsmEJ#bisection > syzbot can test patches for this bug, for details see: > https://goo.gl/tpsmEJ#testing-patches