INFO: task syz.2.11879:14105 blocked for more than 143 seconds. Tainted: G U 6.13.0-syzkaller-05731-g68732c0bf97c #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.2.11879 state:D stack:26800 pid:14105 tgid:14100 ppid:5838 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5377 [inline] __schedule+0x1142/0x5b60 kernel/sched/core.c:6764 __schedule_loop kernel/sched/core.c:6841 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6856 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6913 __mutex_lock_common kernel/locking/mutex.c:662 [inline] __mutex_lock+0x6bd/0xb10 kernel/locking/mutex.c:730 nfsd_nl_rpc_status_get_dumpit+0xb1/0x1160 fs/nfsd/nfsctl.c:1558 genl_dumpit+0x122/0x230 net/netlink/genetlink.c:1027 netlink_dump+0x53c/0xd00 net/netlink/af_netlink.c:2318 __netlink_dump_start+0x6d9/0x980 net/netlink/af_netlink.c:2433 genl_family_rcv_msg_dumpit+0x1e1/0x2e0 net/netlink/genetlink.c:1076 genl_family_rcv_msg net/netlink/genetlink.c:1192 [inline] genl_rcv_msg+0x470/0x800 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x165/0x410 net/netlink/af_netlink.c:2543 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1322 [inline] netlink_unicast+0x53c/0x7f0 net/netlink/af_netlink.c:1348 netlink_sendmsg+0x8b8/0xd70 net/netlink/af_netlink.c:1892 sock_sendmsg_nosec net/socket.c:713 [inline] __sock_sendmsg net/socket.c:728 [inline] ____sys_sendmsg+0x9ae/0xb40 net/socket.c:2568 ___sys_sendmsg+0x135/0x1e0 net/socket.c:2622 __sys_sendmsg+0x16e/0x220 net/socket.c:2654 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc27898cd29 RSP: 002b:00007fc279886038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fc278ba6080 RCX: 00007fc27898cd29 RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000003 RBP: 00007fc278a0e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007fc278ba6080 R15: 00007fff8c7d4808 Showing all locks held in the system: 1 lock held by khungtaskd/30: #0: ffffffff8e1bd600 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8e1bd600 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8e1bd600 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x7f/0x390 kernel/locking/lockdep.c:6746 7 locks held by kworker/u8:4/61: 2 locks held by kworker/u9:1/5145: #0: ffff888025f5b148 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_one_work+0x12cd/0x1b30 kernel/workqueue.c:3211 #1: ffffc900106efd18 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x8bb/0x1b30 kernel/workqueue.c:3212 2 locks held by kworker/u9:2/5839: #0: ffff8880264d9948 ((wq_completion)nbd2-recv){+.+.}-{0:0}, at: process_one_work+0x12cd/0x1b30 kernel/workqueue.c:3211 #1: ffffc90003f8fd18 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x8bb/0x1b30 kernel/workqueue.c:3212 2 locks held by kworker/u9:3/5841: #0: ffff888026593148 ((wq_completion)nbd6-recv ){+.+.}-{0:0}, at: process_one_work+0x12cd/0x1b30 kernel/workqueue.c:3211 #1: ffffc90003fafd18 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x8bb/0x1b30 kernel/workqueue.c:3212 2 locks held by kworker/u9:4/5843: #0: ffff8880264e8148 ((wq_completion)nbd3-recv ){+.+.}-{0:0} , at: process_one_work+0x12cd/0x1b30 kernel/workqueue.c:3211 #1: ffffc90003fefd18 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x8bb/0x1b30 kernel/workqueue.c:3212 2 locks held by kworker/u9:6/15255: #0: ffff8880265fb148 ((wq_completion)nbd7-recv){+.+.}-{0:0}, at: process_one_work+0x12cd/0x1b30 kernel/workqueue.c:3211 #1: ffffc90003d5fd18 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x8bb/0x1b30 kernel/workqueue.c:3212 2 locks held by getty/25722: #0: ffff88814d4fc0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900030e52f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0xfba/0x1480 drivers/tty/n_tty.c:2211 2 locks held by syz.2.11879/14102: #0: ffffffff8ff79f30 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e5c0748 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xe3/0x1b40 fs/nfsd/nfsctl.c:1964 3 locks held by syz.2.11879/14105: #0: ffffffff8ff79f30 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffff8880837ef6c8 (nlk_cb_mutex-GENERIC){+.+.}-{4:4}, at: __netlink_dump_start+0x154/0x980 net/netlink/af_netlink.c:2397 #2: ffffffff8e5c0748 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_rpc_status_get_dumpit+0xb1/0x1160 fs/nfsd/nfsctl.c:1558 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Tainted: G U 6.13.0-syzkaller-05731-g68732c0bf97c #0 Tainted: [U]=USER Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:234 [inline] watchdog+0xf14/0x1240 kernel/hung_task.c:397 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 76 Comm: kworker/u8:5 Tainted: G U 6.13.0-syzkaller-05731-g68732c0bf97c #0 Tainted: [U]=USER Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Workqueue: xprtiod xs_tcp_setup_socket RIP: 0010:io_serial_out+0x8f/0xb0 drivers/tty/serial/8250/8250_port.c:416 Code: 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 1c 66 03 5d 40 44 89 e8 89 da ee <5b> 5d 41 5c 41 5d c3 cc cc cc cc e8 b1 58 e3 fc eb a0 e8 3a 59 e3 RSP: 0018:ffffc9000219f768 EFLAGS: 00000002 RAX: 0000000000000032 RBX: 00000000000003f8 RCX: 0000000000000000 RDX: 00000000000003f8 RSI: ffffffff853879e5 RDI: ffffffff9aacf4e0 RBP: ffffffff9aacf4a0 R08: 0000000000000001 R09: 000000000000001f R10: 0000000000000000 R11: 0000000000000006 R12: 0000000000000000 R13: 0000000000000032 R14: ffffffff85387980 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff55636a9b8 CR3: 0000000020efc000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: serial_out drivers/tty/serial/8250/8250.h:142 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3342 [inline] serial8250_console_write+0xf9e/0x17c0 drivers/tty/serial/8250/8250_port.c:3413 console_emit_next_record kernel/printk/printk.c:3122 [inline] console_flush_all+0x800/0xc60 kernel/printk/printk.c:3210 __console_flush_and_unlock kernel/printk/printk.c:3269 [inline] console_unlock+0xd9/0x210 kernel/printk/printk.c:3309 vprintk_emit+0x41b/0x6f0 kernel/printk/printk.c:2432 _printk+0xc8/0x100 kernel/printk/printk.c:2457 xs_tcp_setup_socket+0x424/0xe30 net/sunrpc/xprtsock.c:2474 process_one_work+0x958/0x1b30 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3317 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244