INFO: task syz.4.996:7193 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.996       state:D stack:0     pid:7193  ppid:4331   flags:0x00000001
Call trace:
 __switch_to+0x2f4/0x550 arch/arm64/kernel/process.c:555
 context_switch kernel/sched/core.c:5257 [inline]
 __schedule+0xdb4/0x1aa4 kernel/sched/core.c:6584
 schedule+0xc4/0x170 kernel/sched/core.c:6660
 schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:6719
 __mutex_lock_common+0xb38/0x1f88 kernel/locking/mutex.c:679
 __mutex_lock kernel/locking/mutex.c:747 [inline]
 mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
 write_ports+0xbc/0x9f0 fs/nfsd/nfsctl.c:846
 nfsctl_transaction_write+0x114/0x164 fs/nfsd/nfsctl.c:114
 vfs_write+0x2a8/0x7c8 fs/read_write.c:582
 ksys_write+0x12c/0x228 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __arm64_sys_write+0x7c/0x90 fs/read_write.c:646
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x12c arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:589

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffff8000165b7ed0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x40/0xc64 kernel/rcu/tasks.h:543
1 lock held by rcu_tasks_trace/13:
 #0: ffff8000165b8710 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x40/0xc64 kernel/rcu/tasks.h:543
1 lock held by khungtaskd/28:
 #0: ffff8000165b7580 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:349
2 locks held by getty/4083:
 #0: ffff0000d757c098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
 #1: ffff80001fa562f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x2e8/0xffc drivers/tty/n_tty.c:2198
3 locks held by syz.4.996/7189:
 #0: ffff0000dcadeae8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x118/0x17c fs/file.c:1038
 #1: ffff0000c3c28460 (sb_writers#12){.+.+}-{0:0}, at: vfs_write+0x254/0x7c8 fs/read_write.c:580
 #2: ffff8000168448e8 (nfsd_mutex){+.+.}-{3:3}, at: write_ports+0xbc/0x9f0 fs/nfsd/nfsctl.c:846
3 locks held by syz.4.996/7193:
 #0: ffff0000ddaa99e8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x118/0x17c fs/file.c:1038
 #1: ffff0000c3c28460 (sb_writers#12){.+.+}-{0:0}, at: vfs_write+0x254/0x7c8 fs/read_write.c:580
 #2: ffff8000168448e8 (nfsd_mutex){+.+.}-{3:3}, at: write_ports+0xbc/0x9f0 fs/nfsd/nfsctl.c:846
1 lock held by syz-executor/8073:
 #0: ffff8000165bd2b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
 #0: ffff8000165bd2b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3f8/0x780 kernel/rcu/tree_exp.h:962
1 lock held by syz.0.1437/9373:
1 lock held by syz.8.1445/9415:
 #0: ffff00019e140458 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:549 [inline]
 #0: ffff00019e140458 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock kernel/sched/sched.h:1363 [inline]
 #0: ffff00019e140458 (&rq->__lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1653 [inline]
 #0: ffff00019e140458 (&rq->__lock){-.-.}-{2:2}, at: __schedule+0x2bc/0x1aa4 kernel/sched/core.c:6500
1 lock held by syz.8.1445/9418:
1 lock held by syz.1.1449/9434:
1 lock held by dhcpcd/9442:
 #0: ffff0000feb2e130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1813 [inline]
 #0: ffff0000feb2e130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x48/0xaf4 net/packet/af_packet.c:3291

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