From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oa2-f11.google.com (mail-oa2-f11.google.com [74.125.231.75]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1D68C377EB8 for ; Fri, 28 Aug 2026 07:35:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.231.75 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787902537; cv=none; b=KW2HzczO8Q0Kp7gCIJMYu1QxLFdHeUOAjQwvKCgR2BfJnoSewJYEKcnyZYjpXESNY4c+dmdEbxBw99cKsiy+GyNHEyLB3GTrrjfCxdx1xI29wl834tO1D14RLzYHpSZEaHSD8qYimNFg5EMy98d2DPqPRnl9/vkgI+8n85jtZMY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787902537; c=relaxed/simple; bh=MeYXlJ4iAb29w/4b9sV/1OGhhI9fC3/y3eyFPMIZqlI=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=uMgxVtjeGmmkUf8mWJFXUdkligPhJy1chyaSJgJvMqmyVR+SfbPwOcI/fN9EJpnEG4vZ9ngXrOTJGMXeom193aypkNvVlb3vkSdu1k16tECtf3TOd5W5tGtzmNhePs4Rgla6Wz4HVvJCA3xphcjwZ6afABdPrnaTUkjUODt/xrg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=74.125.231.75 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oa2-f11.google.com with SMTP id 586e51a60fabf-45e2c1e33e1so332847fac.1 for ; Fri, 28 Aug 2026 00:35:35 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787902535; x=1788507335; h=content-type:to:from:subject:message-id:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=Sk3tuujaXEUvd3IIg4mG/osQZBwsOzl7/c/kikiHyYI=; b=R77JVUzHQ7XqHHV5+I6dewoidqx132Bud09T8xBmNy3ioZlcTaDW42UAqOW2/pnp3h uHQkQNY6D2AItmRxYa9OwW8QjB6bHCGf0RyI7SltSmlK2QMIpWpPsuf6VxkH9oMBEFnF q22gYmZcICUUwr+JgU5W4QdpgK+DJc4jSRe1b+BGfkhhcHyxWuphOkvt5JDsuPFGEhgj A1XRq8Qw30FMLGD9EOnlgbpgKUqYL6pmgNQ9GJ4OSUuYwj47eIVC06rcCFeZji7ABkUM cFaCruDYWyOpEO1vcDGhBBJu9MHlNfcvVIyE8OWxiI7dE9V8Ew2USXZmvjl7/0wQvRzU LPGQ== X-Forwarded-Encrypted: i=1; AHgh+RrLFvTiwQWemPIndJyKYvslMDVWUARVXsf2rezxzfFgW1rj4w0mhacVo++UhLYnguBGkHF927tE3P8=@vger.kernel.org X-Gm-Message-State: AFuF++nG7/KFpHlkCrCpTJ3uGPrZJaaxyiCgc+rLyeW4H9ei3GOa6EH0 gPinCfdcDA/NeEYJlG35gTYXHWDzu5CoPajmNiuBv8ZaAWTzGeGrFuGH8aYYpISZSBi8FCB/9kw 158fmBJvl0fJcoVcXwlUE0ZuDnGTXCGQ5y8m9ebBX5maZZBFLSSIwOy0hk2s= Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:2017:b0:6b1:5d5e:679d with SMTP id 006d021491bc7-6b1c679e571mr4354363eaf.28.1787902534866; Fri, 28 Aug 2026 00:35:34 -0700 (PDT) Date: Fri, 28 Aug 2026 00:35:34 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a913a46.4d659fcc.734b4.001a.GAE@google.com> Subject: [syzbot] [nfs?] INFO: task hung in nfsd_nl_unlock_filesystem_doit From: syzbot To: Dai.Ngo@oracle.com, cel@kernel.org, jlayton@kernel.org, linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, neil@brown.name, okorniev@redhat.com, syzkaller-bugs@googlegroups.com, tom@talpey.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 45c13f3f9e3b Merge tag 'hwlock-v7.3' of git://git.kernel.o.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=16068d49580000 kernel config: https://syzkaller.appspot.com/x/.config?x=c4f4455f41cf6a92 dashboard link: https://syzkaller.appspot.com/bug?extid=0093d3ab8d8eb2fdde82 compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/82d12e132e96/disk-45c13f3f.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/46f8d07d4673/vmlinux-45c13f3f.xz kernel image: https://storage.googleapis.com/syzbot-assets/02439192d277/bzImage-45c13f3f.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+0093d3ab8d8eb2fdde82@syzkaller.appspotmail.com INFO: task syz.2.1768:11730 blocked for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.2.1768 state:D stack:28144 pid:11730 tgid:11729 ppid:5602 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5520 [inline] __schedule+0x1259/0x6920 kernel/sched/core.c:7270 __schedule_loop kernel/sched/core.c:7347 [inline] schedule+0xdd/0x2c0 kernel/sched/core.c:7362 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7419 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0xcbf/0x1bc0 kernel/locking/mutex.c:821 nfsd_nl_unlock_filesystem_doit+0x203/0x410 fs/nfsd/nfsctl.c:2677 genl_family_rcv_msg_doit+0x214/0x300 net/netlink/genetlink.c:1114 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline] genl_rcv_msg+0x560/0x800 net/netlink/genetlink.c:1209 netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2556 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec net/socket.c:800 [inline] __sock_sendmsg net/socket.c:815 [inline] ____sys_sendmsg+0xa4d/0xbe0 net/socket.c:2713 ___sys_sendmsg+0x190/0x1e0 net/socket.c:2767 __sys_sendmsg+0x160/0x210 net/socket.c:2799 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f88cbb9e0d9 RSP: 002b:00007f88cca9f028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f88cbe25fa0 RCX: 00007f88cbb9e0d9 RDX: 0000000004000080 RSI: 0000200000000100 RDI: 0000000000000003 RBP: 00007f88cbc35024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f88cbe26038 R14: 00007f88cbe25fa0 R15: 00007ffd44e926f8 Showing all locks held in the system: locks held by khungtaskd/32: 1, last CPU#0: #0: ffffffff8edec060 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] #0: ffffffff8edec060 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8edec060 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6793 locks held by udevd/4965: 1, on CPU#0: #0: ffff88801d2bf180 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_dop_revalidate+0xa5/0x7e0 fs/kernfs/dir.c:1217 locks held by getty/5352: 2, on CPU#1: #0: ffff8880380ee0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14e0 drivers/tty/n_tty.c:2211 locks held by kworker/0:6/5706: 3, on CPU#0: #0: ffff88801c057140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3362 #1: ffffc90004c37d08 (deferred_process_work){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3363 #2: ffffffff90cc9840 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104 locks held by syz.0.1424/10896: 2, on CPU#0: #0: ffffffff90d78be8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff8f284440 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x1a3/0x1dc0 fs/nfsd/nfsctl.c:2057 locks held by syz.2.1768/11730: 2, on CPU#1: #0: ffffffff90d78be8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff8f284440 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_unlock_filesystem_doit+0x203/0x410 fs/nfsd/nfsctl.c:2677 locks held by syz.1.2261/12930: 2, on CPU#1: #0: ffff888055b400e8 (&type->s_umount_key#75){+.+.}-{4:4}, at: __super_lock fs/super.c:60 [inline] #0: ffff888055b400e8 (&type->s_umount_key#75){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:75 [inline] #0: ffff888055b400e8 (&type->s_umount_key#75){+.+.}-{4:4}, at: deactivate_super fs/super.c:631 [inline] #0: ffff888055b400e8 (&type->s_umount_key#75){+.+.}-{4:4}, at: deactivate_super+0xe2/0x110 fs/super.c:628 #1: ffffffff8f284440 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:582 locks held by syz-executor/13344: 1, last CPU#0: #0: ffffffff8ef90080 (pcpu_alloc_mutex){+.+.}-{4:4}, at: pcpu_alloc_noprof+0xfa8/0x1e50 mm/percpu.c:1796 locks held by syz.5.3369/16148: 4, last CPU#0: #0: ffff88804d75d1b0 (&tty->legacy_mutex){+.+.}-{4:4}, at: tty_init_dev.part.0+0x39/0x470 drivers/tty/tty_io.c:1379 #1: ffff888031c242a8 (&port->mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline] #1: ffff888031c242a8 (&port->mutex){+.+.}-{4:4}, at: tty_port_open+0x8e/0x1f0 drivers/tty/tty_port.c:764 #2: ffff888027933d18 (&serial->disc_mutex){+.+.}-{4:4}, at: serial_port_activate+0x52/0x290 drivers/usb/serial/usb-serial.c:258 #3: ffff8880887f8460 (&tdev->td_open_close_lock){+.+.}-{4:4}, at: ti_open+0xb4/0xce0 drivers/usb/serial/ti_usb_3410_5052.c:653 locks held by syz.3.3374/16166: 4, last CPU#0: #0: ffffffff90c998a0 (br_ioctl_mutex){+.+.}-{4:4}, at: br_ioctl_call+0x34/0xa0 net/socket.c:1296 #1: ffffffff90cc9840 (rtnl_mutex){+.+.}-{4:4}, at: br_ioctl_stub+0x2af/0x4d0 net/bridge/br_ioctl.c:418 #2: ffff88801d2bf180 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_add_one+0x38/0xaa0 fs/kernfs/dir.c:825 #3: ffff88801d2bf210 (&root->kernfs_iattr_rwsem){++++}-{4:4}, at: kernfs_link_sibling+0x555/0x850 fs/kernfs/dir.c:411 locks held by syz.6.3376/16171: 1, last CPU#0: #0: ffff88802cf9f470 (&u->iolock){+.+.}-{4:4}, at: __unix_dgram_recvmsg+0x255/0xc30 net/unix/af_unix.c:2587 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 32 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:123 nmi_trigger_cpumask_backtrace+0x21f/0x2a0 lib/nmi_backtrace.c:66 trigger_all_cpu_backtrace include/linux/nmi.h:164 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x141/0x190 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline] watchdog+0xcb1/0x1030 kernel/hung_task.c:561 kthread+0x373/0x450 kernel/kthread.c:436 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 --- 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. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup