INFO: task syz.0.677:8529 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.677       state:D stack:0     pid:8529  tgid:8528  ppid:6548   task_flags:0x400140 flags:0x00000011
Call trace:
 __switch_to+0x418/0x87c arch/arm64/kernel/process.c:741 (T)
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x13b0/0x2864 kernel/sched/core.c:6929
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0xb4/0x230 kernel/sched/core.c:7026
 schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:7083
 __mutex_lock_common+0xd04/0x2678 kernel/locking/mutex.c:676
 __mutex_lock kernel/locking/mutex.c:760 [inline]
 mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:812
 nfsd_nl_threads_set_doit+0x270/0x888 fs/nfsd/nfsctl.c:1590
 genl_family_rcv_msg_doit+0x1d8/0x2bc net/netlink/genetlink.c:1115
 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
 genl_rcv_msg+0x450/0x624 net/netlink/genetlink.c:1210
 netlink_rcv_skb+0x220/0x3fc net/netlink/af_netlink.c:2552
 genl_rcv+0x38/0x50 net/netlink/genetlink.c:1219
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x694/0x8c4 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x648/0x930 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg net/socket.c:742 [inline]
 ____sys_sendmsg+0x490/0x7b8 net/socket.c:2630
 ___sys_sendmsg+0x204/0x278 net/socket.c:2684
 __sys_sendmsg net/socket.c:2716 [inline]
 __do_sys_sendmsg net/socket.c:2721 [inline]
 __se_sys_sendmsg net/socket.c:2719 [inline]
 __arm64_sys_sendmsg+0x184/0x238 net/socket.c:2719
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:746
 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:765
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596

Showing all locks held in the system:
2 locks held by ksoftirqd/0/14:
1 lock held by khungtaskd/32:
 #0: ffff80008f76b5a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire+0x4/0x48 include/linux/rcupdate.h:330
2 locks held by getty/6331:
 #0: ffff0000d89da0a0 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
 #1: ffff80009bb2b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x34c/0xfa4 drivers/tty/n_tty.c:2222
2 locks held by syz.2.370/7806:
 #0: ffff8000928be050 (cb_lock){++++}-{4:4}, at: genl_rcv+0x28/0x50 net/netlink/genetlink.c:1218
 #1: ffff80008fa49c68 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x10c/0x1294 fs/nfsd/nfsctl.c:1880
2 locks held by syz.0.677/8529:
 #0: ffff8000928be050 (cb_lock){++++}-{4:4}, at: genl_rcv+0x28/0x50 net/netlink/genetlink.c:1218
 #1: ffff80008fa49c68 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x270/0x888 fs/nfsd/nfsctl.c:1590
3 locks held by syz-executor/10714:
1 lock held by syz.8.2101/13018:
1 lock held by syz.8.2101/13019:

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