From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo2-f7.google.com (mail-oo2-f7.google.com [74.125.231.135]) (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 2B57E361979 for ; Thu, 3 Sep 2026 22:38:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.231.135 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788475122; cv=none; b=s2WxUh3FjzNx5WMC5l17xmCH/7yx7oy95HORKyz+X1D0qgFzDuqwkZIq1h2MY/wX9X7MVCnZlGiYVtG3wN6tridJBrxmuUrycInOZ0n+ZVOLALHSz4lMp4hBqcXaTg2dt0f/yeU7CAGzFqbb3NZEqTHBZxNYVcaxC7t9W4gm0Ew= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788475122; c=relaxed/simple; bh=srKtBN7YiWfEJnHZlCVPhTL+BXHoTKstoVhYCmwaebM=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=spYWgPmN6ol1BOcbRZ9pYR/OeL0N5FthoW6wxHCznlCtDvrFCETHXqGxQ38k+dH701mNKv9/El7qP4QWfwC8UhU62OpXeL8eKiCKtgfq/34Lwb/qxTodtOi449rbwq1rMZ2aHyRRSTirE+d88gGMF51VTyul5S1czgxMgHZWmz4= 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=74.125.231.135 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-oo2-f7.google.com with SMTP id 006d021491bc7-6b137c364c5so74181eaf.1 for ; Thu, 03 Sep 2026 15:38:41 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1788475120; x=1789079920; 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=XSguvTv0VEWmcSNYt7WY8UZQpYNnQc+lL3sqxL8n/LE=; b=IMIPmWmBZAES5/DaEhc7qNLn4OdL1GEuQ3SN3zJC15wlsMuear/h8kx5mm0N5g+U2f oIu5bO2tG/mzwbJtErf41VD7x0L/4H/BNfVkVtTMl1Ch0eCrWm/qRM5/un58llM/n1Ue 1E1NmqGuBQtWpyw/Z9vGiJ5ReFMRsfU+uCvXKhZPntBK4WWV8Fb6SpqHCeyC/hgG2QRU /zUVFiDvm7eu6VwlS4Ell5nxDQ7odZ/eIlC2mQjH8Oq/Ry7xJ9MJjn8PktQbaiK5UK9W BcULakehCAaf1gmprw4qPOodI05u9uoIt+HErsizzqj5GARO9ER1YshYZmJ2zO4SvHLt FZAg== X-Forwarded-Encrypted: i=1; AKwUvBwrbiAxP7tZEmtzv0FF5cCBc1DLER6fjugRGafVDYLl2rHKjCPmS3VlGuQvKlJPOnhp/9xRfu10d+NMoh0=@vger.kernel.org X-Gm-Message-State: AFuF++l71jm2GlJNhG29Sb33joZ/U4sRtWS8gsIP2CEwqSf+CnGRIsQb HdIgxEXNcTfrukhho37tvFY2Xy3RJcbp2pqaHIPIKEc3wKjQr3GpJYpFeZfHCXP1g+9XjK8XhdO sqa0XS4/CCu1QRG5o7KOsOaJXbqMaq6YJRD6U+KaCn55mYF7VKAMYnAjQa1A= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a4a:ec4a:0:b0:6b7:46fc:1dd with SMTP id 006d021491bc7-6b746fc025cmr152867eaf.60.1788475120144; Thu, 03 Sep 2026 15:38:40 -0700 (PDT) Date: Thu, 03 Sep 2026 15:38:40 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a99f6f0.2e567484.299ffc.000c.GAE@google.com> Subject: [syzbot] [nfs?] INFO: task hung in nfsd4_cld_tracking_init 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: 940de590b839 Merge tag 'hardening-v7.3-rc2' of git://git.k.. git tree: upstream console+strace: https://syzkaller.appspot.com/x/log.txt?x=12c6b39e580000 kernel config: https://syzkaller.appspot.com/x/.config?x=8c5c3949d762a91f dashboard link: https://syzkaller.appspot.com/bug?extid=edbebd898142ee5e24ce 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=14872125580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12b8cb49580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/75055d1d5648/disk-940de590.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/419590aed71c/vmlinux-940de590.xz kernel image: https://storage.googleapis.com/syzbot-assets/c51c5e853b44/bzImage-940de590.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+edbebd898142ee5e24ce@syzkaller.appspotmail.com INFO: task syz-executor22 INFO: task syz-executor224:5626 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor224 state:D stack:24312 pid:5626 tgid:5625 ppid:5624 task_flags:0x400140 flags:0x00080802 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_timeout+0x1b2/0x280 kernel/time/sleep_timeout.c:75 do_wait_for_common kernel/sched/completion.c:100 [inline] __wait_for_common+0x2e7/0x4c0 kernel/sched/completion.c:121 __cld_pipe_upcall fs/nfsd/nfs4recover.c:673 [inline] cld_pipe_upcall fs/nfsd/nfs4recover.c:691 [inline] nfsd4_cld_get_version fs/nfsd/nfs4recover.c:1425 [inline] nfsd4_cld_tracking_init+0x4be/0x10f0 fs/nfsd/nfs4recover.c:1490 nfsd4_client_tracking_init+0xe5/0x1c0 fs/nfsd/nfs4recover.c:1941 nfs4_state_start_net.cold+0xb7/0x480 fs/nfsd/nfs4state.c:9838 nfsd_startup_net fs/nfsd/nfssvc.c:391 [inline] nfsd_svc+0x54a/0x7d0 fs/nfsd/nfssvc.c:775 write_threads+0x316/0x600 fs/nfsd/nfsctl.c:438 nfsctl_transaction_write+0x106/0x1a0 fs/nfsd/nfsctl.c:114 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:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbfd3713269 RSP: 002b:00007fbfd36eb1d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fbfd37c3b68 RCX: 00007fbfd3713269 RDX: 0000000000000002 RSI: 0000200000000100 RDI: 0000000000000005 RBP: 00007fbfd37c3b60 R08: 35203a6b63617473 R09: 35203a6b63617473 R10: 35203a6b63617473 R11: 0000000000000246 R12: 00007fbfd3795378 R13: 0000200000000200 R14: 0000200000000500 R15: 00002000000000c0 Showing all locks held in the system: locks held by kworker/u8:1/13: 2, on CPU#0: #0: ffff88801c094140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3371 #1: ffffc90000127d08 ((work_completion)(&(&kfence_timer)->work)){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3372 locks held by pr/ttyS0/16: 2, last CPU#0: #0: ffffffff8edd8338 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:314 [inline] #0: ffffffff8edd8338 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:439 [inline] #0: ffffffff8edd8338 (console_srcu){....}-{0:0}, at: console_srcu_read_lock+0x49/0x60 kernel/printk/printk.c:291 #1: ffffffff9bc63c78 (&port_lock_key){-.-.}-{3:3}, at: __uart_port_lock_irqsave include/linux/serial_core.h:613 [inline] #1: ffffffff9bc63c78 (&port_lock_key){-.-.}-{3:3}, at: univ8250_console_device_lock+0x64/0xc0 drivers/tty/serial/8250/8250_core.c:413 locks held by khungtaskd/32: 1, last CPU#1: #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:6837 locks held by getty/5360: 2, on CPU#1: #0: ffff888029f520a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900032262e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14e0 drivers/tty/n_tty.c:2211 locks held by syz-executor224/5626: 3, on CPU#1: #0: ffff88802b935970 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259 #1: ffff888035040460 (sb_writers#9){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739 #2: ffffffff8f287680 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x288/0x600 fs/nfsd/nfsctl.c:436 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 32 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026 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 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 16 Comm: pr/ttyS0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026 RIP: 0010:io_serial_in+0x87/0xb0 drivers/tty/serial/8250/8250_port.c:410 Code: 07 5c fc 48 8d 7d 40 44 89 e1 48 b8 00 00 00 00 00 fc ff df 48 89 fa d3 e3 48 c1 ea 03 80 3c 02 00 75 1a 66 03 5d 40 89 da ec <5b> 0f b6 c0 5d 41 5c c3 cc cc cc cc e8 48 1a cf fc eb a2 e8 d1 1a RSP: 0018:ffffc90000157958 EFLAGS: 00000002 RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000 RDX: 00000000000003fd RSI: ffffffff85afe8d0 RDI: ffffffff9bc63ca0 RBP: ffffffff9bc63c60 R08: 0000000000000001 R09: 000000000000001f R10: 0000000000000000 R11: 205d323354202020 R12: 0000000000000000 R13: 0000000000000020 R14: fffffbfff378c7e9 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888123b61000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000561b47b0e660 CR3: 000000000eb96000 CR4: 00000000003526f0 Call Trace: serial_in drivers/tty/serial/8250/8250.h:128 [inline] serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline] wait_for_lsr+0x13a/0x210 drivers/tty/serial/8250/8250_port.c:2013 serial8250_fifo_wait_for_lsr_thre+0x5f/0xd0 drivers/tty/serial/8250/8250_port.c:3270 __serial8250_console_fifo_write+0xa5/0x290 drivers/tty/serial/8250/8250_port.c:3345 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3378 [inline] __serial8250_console_write drivers/tty/serial/8250/8250_port.c:3429 [inline] serial8250_console_write+0xf46/0x1330 drivers/tty/serial/8250/8250_port.c:3493 nbcon_emit_next_record+0x8f7/0xa70 kernel/printk/nbcon.c:1070 nbcon_emit_one+0x1a8/0x2b0 kernel/printk/nbcon.c:1157 nbcon_kthread_func+0x613/0x7d0 kernel/printk/nbcon.c:1271 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 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. 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