INFO: task syz.3.9243:27062 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.9243      state:D stack:24024 pid:27062 tgid:27061 ppid:26291  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x14ef/0x4fb0
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7fe/0x1300
 nfsd_nl_threads_get_doit+0x1ba/0x700
 genl_family_rcv_msg_doit+0x22a/0x330
 genl_rcv_msg+0x61c/0x7a0
 netlink_rcv_skb+0x232/0x4b0
 genl_rcv+0x28/0x40
 netlink_unicast+0x80f/0x9b0
 netlink_sendmsg+0x813/0xb40
 __sock_sendmsg+0x21c/0x270
 ____sys_sendmsg+0x4d7/0x810
 ___sys_sendmsg+0x2a5/0x360
 __x64_sys_sendmsg+0x1bd/0x2a0
 do_syscall_64+0xe2/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc1cb19acb9
RSP: 002b:00007fc1cc093028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fc1cb415fa0 RCX: 00007fc1cb19acb9
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000005
RBP: 00007fc1cb208bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc1cb416038 R14: 00007fc1cb415fa0 R15: 00007fffb37e3638
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/35:
 #0: ffffffff8e35a320 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by kworker/u9:6/1096:
 #0: ffff888100089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0
 #1: ffffc9000835fbc0 ((work_completion)(&(&kfence_timer)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0
2 locks held by getty/5650:
 #0: ffff888176ecf0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900029e02f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0
3 locks held by kworker/u11:4/5883:
 #0: ffff88816a33e948 ((wq_completion)hci0){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0
 #1: ffffc90005267bc0 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0
 #2: ffff888169b18ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_cmd_sync_work+0x1d3/0x400
2 locks held by syz.2.8619/25647:
 #0: ffffffff8f816b30 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8e678968 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x141/0x16c0
2 locks held by syz.3.9243/27062:
 #0: ffffffff8f816b30 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8e678968 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_get_doit+0x1ba/0x700

=============================================

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 35 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 nmi_cpu_backtrace+0x274/0x2d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 sys_info+0x135/0x170
 watchdog+0xf90/0xfe0
 kthread+0x726/0x8b0
 ret_from_fork+0x51b/0xa40
 ret_from_fork_asm+0x1a/0x30
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:pv_native_safe_halt+0xf/0x20
Code: 88 5f 02 e9 d3 e5 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa eb 07 0f 00 2d d3 d7 10 00 fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffc90000197e20 EFLAGS: 00000206
RAX: 00000000002c2511 RBX: ffffffff8198335d RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8dad4762 RDI: ffffffff8be73880
RBP: ffffc90000197f10 R08: ffff88823c6336db R09: 1ffff110478c66db
R10: dffffc0000000000 R11: ffffed10478c66dc R12: ffffffff8fced770
R13: 1ffff1102c155000 R14: 0000000000000001 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8882a9929000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff559de3358 CR3: 00000001745de000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 default_idle+0x9/0x20
 default_idle_call+0x72/0xb0
 do_idle+0x1bd/0x500
 cpu_startup_entry+0x43/0x60
 start_secondary+0x101/0x110
 common_startup_64+0x13e/0x147
 </TASK>
