From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f80.google.com (mail-oo1-f80.google.com [209.85.161.80]) (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 576372F12A1 for ; Sun, 16 Aug 2026 10:14:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.80 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786875290; cv=none; b=dyFnd+edBxZJ3P+s/qu9sB2kKfsH+I93Uo2bpl4tO6ecx99WXegC/eVBsqv2myFAmbsgWhdq2WWBPu66gYzh3H3mQrlpWPmhRrpUx7m4NcRPsA04ozQstw6+Mrg+PnAfelHpqcJEJ54+rFlVQCX4Zkb8mTuuoqawEZZv8JAoLWs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786875290; c=relaxed/simple; bh=CnUziLPxDwi1d8oEi6FGbhwhdTNT2X1qbbd+TDUnxmQ=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=W4Yl2BxNEFf6/YeEHzeowWy1eMm2zd7JEBquVefn9RxUPfx6F9eS2zfeGfYDjcahwNXC5WpPPJXN4G+hTt5S4HJ7QOqz+2E1TCtiKDxyFn1LJcsKM9b72ZUPfdjmak58ykPvsNNjX2Ya7i3E5Fp1Gknmeyx/GEvVj1kypSVOk8Q= 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=209.85.161.80 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-oo1-f80.google.com with SMTP id 006d021491bc7-6aae6f87ed7so2618675eaf.0 for ; Sun, 16 Aug 2026 03:14:48 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786875287; x=1787480087; h=content-type:to:from:subject:message-id:in-reply-to:date :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to:content-type; bh=s8mMt6t+qmsxh+EXL48+rnT3tSBb6+h53O/fAmBIDoc=; b=Go9XvHAIeCsOKkWDqoO3VIOviGGIJAGfNooXFzXgjkDFmeS0nGyHHmi91v4jwolk4T 4qpXIwca23ZebxjZ7Jt2mLjhY6OxOjrXulcoNu9C1s8b6Zx6ye/lwYotosFTzl7HGVHI O2k3Ka22B3/utjRTUGrgi38AoonfMnRuHNCpDYD1BsR8D9F5a6u0LmYJuPQWvwVy0Alg F6+oNJ45+KGeT+5kqFLZbfG4j+PcmnU8B3vz8C52OUj7eP+ELSctsqlHJv6BxrrQb4dj wmEiJM2Re2LsBbeSIgAthx1MiIiNZ8zxUbkqIKD4TC5op0hHfC1Y+a6eOufkBS/rT0Kb Qpqw== X-Forwarded-Encrypted: i=1; AHgh+RocVVsW63SA1upvUMfDC9NBWz4QoqNNfFnboqFYbdZ3bwGbLTBDbI8sn2SKcYS7srhu/zV4kXUn3VxSSQU=@vger.kernel.org X-Gm-Message-State: AOJu0YwNbxN5LHRk2jB7sNURS96awGgrfcGBzac+LYBZPcq0nhcV9f41 5N9j4Gk2o4vdrFTp2KXxM3Z3JG1yAA+AtkKkPqUmw9Gb/10Vd+NkFw7W5ppcTKneE69hmUxYzjK XUPyittMqJOSptT116lUhRsTnN50r8DIv95GWRtQPqt5dJbYQOmQ/Tp8pc/w= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:3083:b0:6a3:8023:f344 with SMTP id 006d021491bc7-6b0d5fa5231mr16225259eaf.2.1786875287329; Sun, 16 Aug 2026 03:14:47 -0700 (PDT) Date: Sun, 16 Aug 2026 03:14:47 -0700 In-Reply-To: <000000000000f8ed54061ca0d9a5@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a818d97.9ebadd4d.20b15e.0015.GAE@google.com> Subject: Re: [syzbot] [nfs?] INFO: task hung in nfsd_umount From: syzbot To: Dai.Ngo@oracle.com, cel@kernel.org, chuck.lever@oracle.com, dai.ngo@oracle.com, harri@afaics.de, jlayton@kernel.org, kolga@netapp.com, linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, neil@brown.name, neilb@suse.de, okorniev@redhat.com, syzkaller-bugs@googlegroups.com, tom@talpey.com Content-Type: text/plain; charset="UTF-8" syzbot has found a reproducer for the following issue on: HEAD commit: 3eb40771c00a Merge tag 'soc-fixes-7.2-3' of git://git.kern.. git tree: upstream console+strace: https://syzkaller.appspot.com/x/log.txt?x=1309ba79580000 kernel config: https://syzkaller.appspot.com/x/.config?x=1d67342c314f228d dashboard link: https://syzkaller.appspot.com/bug?extid=b568ba42c85a332a88ee compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=156daa25580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13ad9a79580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/21569197c3cb/disk-3eb40771.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/09af5299a851/vmlinux-3eb40771.xz kernel image: https://storage.googleapis.com/syzbot-assets/c657b46695b7/bzImage-3eb40771.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+b568ba42c85a332a88ee@syzkaller.appspotmail.com INFO: task syz-executor347:5620 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor347 state:D stack:22184 pid:5620 tgid:5620 ppid:5617 task_flags:0x400140 flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0xdd/0x2c0 kernel/sched/core.c:7326 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0xccc/0x1bd0 kernel/locking/mutex.c:821 nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576 nfsd_umount+0x3b/0x60 fs/nfsd/nfsctl.c:1365 deactivate_locked_super+0xc1/0x1b0 fs/super.c:477 deactivate_super fs/super.c:510 [inline] deactivate_super+0xe7/0x110 fs/super.c:506 cleanup_mnt+0x21f/0x450 fs/namespace.c:1317 task_work_run+0x150/0x240 kernel/task_work.c:233 ptrace_notify+0xf3/0x120 kernel/signal.c:2531 ptrace_report_syscall include/linux/ptrace.h:416 [inline] ptrace_report_syscall_exit include/linux/ptrace.h:478 [inline] arch_ptrace_report_syscall_exit include/linux/entry-common.h:213 [inline] syscall_exit_work include/linux/entry-common.h:248 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:279 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:316 [inline] do_syscall_64+0x6c0/0x870 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f056f6eec17 RSP: 002b:00007ffff209c618 EFLAGS: 00000206 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 000000000001399c RCX: 00007f056f6eec17 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffff209c6d0 RBP: 00007ffff209c6d0 R08: 00007ffff209d6d0 R09: 00000000ffffffff R10: 0000000000000000 R11: 0000000000000206 R12: 00007ffff209d740 R13: 0000555587301780 R14: 00007ffff209d740 R15: 0000000000000001 INFO: task syz-executor347:5775 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor347 state:D stack:27448 pid:5775 tgid:5775 ppid:5618 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0xdd/0x2c0 kernel/sched/core.c:7326 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0xccc/0x1bd0 kernel/locking/mutex.c:821 write_ports+0xa5/0xcc0 fs/nfsd/nfsctl.c:860 nfsctl_transaction_write+0x106/0x1a0 fs/nfsd/nfsctl.c:112 vfs_write+0x2aa/0x1050 fs/read_write.c:685 ksys_write+0x12a/0x250 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f056f6eea19 RSP: 002b:00007ffff209d708 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 645f6473666e2f2e RCX: 00007f056f6eea19 RDX: 0000000000000005 RSI: 0000200000000700 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007f056f75a222 R09: 00007f056f75a222 R10: 00007f056f75a222 R11: 0000000000000246 R12: 00007f056f75a47b R13: 0000000000000001 R14: 00007ffff209d740 R15: 0000000000000000 INFO: task syz-executor347:5776 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor347 state:D stack:27088 pid:5776 tgid:5776 ppid:5615 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0xdd/0x2c0 kernel/sched/core.c:7326 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0xccc/0x1bd0 kernel/locking/mutex.c:821 write_ports+0xa5/0xcc0 fs/nfsd/nfsctl.c:860 nfsctl_transaction_write+0x106/0x1a0 fs/nfsd/nfsctl.c:112 vfs_write+0x2aa/0x1050 fs/read_write.c:685 ksys_write+0x12a/0x250 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f056f6eea19 RSP: 002b:00007ffff209d708 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 645f6473666e2f2e RCX: 00007f056f6eea19 RDX: 0000000000000005 RSI: 0000200000000700 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007f056f75a222 R09: 00007f056f75a222 R10: 00007f056f75a222 R11: 0000000000000246 R12: 00007f056f75a47b R13: 0000000000000001 R14: 00007ffff209d740 R15: 0000000000000000 INFO: task syz-executor347:5777 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor347 state:D stack:27848 pid:5777 tgid:5777 ppid:5614 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0xdd/0x2c0 kernel/sched/core.c:7326 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0xccc/0x1bd0 kernel/locking/mutex.c:821 write_ports+0xa5/0xcc0 fs/nfsd/nfsctl.c:860 nfsctl_transaction_write+0x106/0x1a0 fs/nfsd/nfsctl.c:112 vfs_write+0x2aa/0x1050 fs/read_write.c:685 ksys_write+0x12a/0x250 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f056f6eea19 RSP: 002b:00007ffff209d708 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 645f6473666e2f2e RCX: 00007f056f6eea19 RDX: 0000000000000005 RSI: 0000200000000700 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007f056f75a222 R09: 00007f056f75a222 R10: 00007f056f75a222 R11: 0000000000000246 R12: 00007f056f75a47b R13: 0000000000000001 R14: 00007ffff209d740 R15: 0000000000000000 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8ede8200 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8ede8200 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #0: ffffffff8ede8200 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775 5 locks held by kworker/u8:6/152: 2 locks held by getty/5348: #0: ffff888037c7d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14e0 drivers/tty/n_tty.c:2211 2 locks held by syz-executor347/5619: #0: ffff88806d1b80d8 (&type->s_umount_key#67){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88806d1b80d8 (&type->s_umount_key#67){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff88806d1b80d8 (&type->s_umount_key#67){+.+.}-{4:4}, at: deactivate_super fs/super.c:509 [inline] #0: ffff88806d1b80d8 (&type->s_umount_key#67){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:506 #1: ffffffff8f272480 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576 2 locks held by syz-executor347/5620: #0: ffff88806d2220d8 (&type->s_umount_key#67){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88806d2220d8 (&type->s_umount_key#67){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff88806d2220d8 (&type->s_umount_key#67){+.+.}-{4:4}, at: deactivate_super fs/super.c:509 [inline] #0: ffff88806d2220d8 (&type->s_umount_key#67){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:506 #1: ffffffff8f272480 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576 2 locks held by syz-executor347/5775: #0: ffff888079e4c450 (sb_writers#9){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739 #1: ffffffff8f272480 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xa5/0xcc0 fs/nfsd/nfsctl.c:860 2 locks held by syz-executor347/5776: #0: ffff88807af5e450 (sb_writers#9){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739 #1: ffffffff8f272480 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xa5/0xcc0 fs/nfsd/nfsctl.c:860 2 locks held by syz-executor347/5777: #0: ffff8880246f6450 (sb_writers#9){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739 #1: ffffffff8f272480 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xa5/0xcc0 fs/nfsd/nfsctl.c:860 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 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:122 nmi_trigger_cpumask_backtrace+0x21c/0x2a0 lib/nmi_backtrace.c:65 trigger_all_cpu_backtrace include/linux/nmi.h:162 [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+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 13 Comm: kworker/u8:1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Workqueue: bat_events batadv_mcast_mla_update RIP: 0010:_static_cpu_has arch/x86/include/asm/cpufeature.h:101 [inline] RIP: 0010:addr_has_metadata mm/kasan/kasan.h:334 [inline] RIP: 0010:check_region_inline mm/kasan/generic.c:188 [inline] RIP: 0010:kasan_check_range+0x31/0x1e0 mm/kasan/generic.c:200 Code: 0f 84 7a 01 00 00 48 89 f8 41 54 41 89 d0 48 01 f0 55 53 0f 82 e6 00 00 00 eb 0f cc cc cc 48 b8 00 00 00 00 00 00 00 ff eb 0a <48> b8 00 00 00 00 00 80 ff ff 48 39 c7 0f 82 c2 00 00 00 4c 8d 54 RSP: 0018:ffffc90000127a60 EFLAGS: 00000282 RAX: ffffc90000127b34 RBX: ffffc90000127b30 RCX: ffffffff8b8815dd RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc90000127b30 RBP: 0000000000000004 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: ffff88807832d8a8 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888123cde000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005620a0b86660 CR3: 000000000eb94000 CR4: 00000000003526f0 Call Trace: __asan_memset+0x23/0x50 mm/kasan/shadow.c:84 batadv_mcast_mla_flags_get net/batman-adv/multicast.c:283 [inline] __batadv_mcast_mla_update net/batman-adv/multicast.c:907 [inline] batadv_mcast_mla_update+0x10d/0x3200 net/batman-adv/multicast.c:946 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322 process_scheduled_works kernel/workqueue.c:3405 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 --- If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing.