INFO: task syz.2.1014:9476 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.1014      state:D stack:25728 pid:9476  tgid:9475  ppid:5849   task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7e6/0x1360
 nfsd_nl_threads_set_doit+0x2cb/0x960
 genl_family_rcv_msg_doit+0x215/0x300
 genl_rcv_msg+0x60e/0x790
 netlink_rcv_skb+0x208/0x470
 genl_rcv+0x28/0x40
 netlink_unicast+0x82f/0x9e0
 netlink_sendmsg+0x805/0xb30
 __sock_sendmsg+0x21c/0x270
 ____sys_sendmsg+0x505/0x830
 ___sys_sendmsg+0x21f/0x2a0
 __x64_sys_sendmsg+0x19b/0x260
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f961ef8ebe9
RSP: 002b:00007f961fd4d038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f961f1c5fa0 RCX: 00007f961ef8ebe9
RDX: 0000000004000000 RSI: 0000200000000780 RDI: 0000000000000009
RBP: 00007f961f011e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f961f1c6038 R14: 00007f961f1c5fa0 R15: 00007ffe9df5f968
 </TASK>

Showing all locks held in the system:
2 locks held by rcu_tasks_trace/32:
1 lock held by khungtaskd/35:
 #0: ffffffff8e139ea0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
3 locks held by kworker/1:1/51:
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc9000079fbc0 (free_ipc_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8e13f938 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730
2 locks held by getty/5671:
 #0: ffff88810fe550a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900029132f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
3 locks held by kworker/u8:3/5871:
 #0: ffff888136639f98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140
 #1: ffff888136624008 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880
 #2: ffff888136625918 (&base->lock){-.-.}-{2:2}, at: __mod_timer+0x1ae/0xf30
3 locks held by kworker/1:5/5908:
2 locks held by syz.2.1014/9476:
 #0: ffffffff8f59d470 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8e418588 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x2cb/0x960
2 locks held by syz.2.1014/9477:
 #0: ffffffff8f59d470 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8e418588 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x2cb/0x960
1 lock held by syz.5.2043/12963:
 #0: ffffffff8e13f938 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730
1 lock held by syz.1.2046/12971:
 #0: ffffffff8e19d448 (event_mutex){+.+.}-{4:4}, at: perf_trace_destroy+0x2e/0x150

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

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+0x189/0x250
 nmi_cpu_backtrace+0x39e/0x3d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 watchdog+0xf93/0xfe0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 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: 5871 Comm: kworker/u8:3 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
Workqueue: bat_events batadv_nc_worker
RIP: 0010:__lock_acquire+0xff/0xd20
Code: 8b b4 24 88 00 00 00 8b 6c 24 78 41 89 d5 48 c7 c1 10 03 49 93 48 29 c8 48 c1 f8 03 48 be 29 5c 8f c2 f5 28 5c 8f 48 0f af f0 <45> 85 f6 0f 85 4a 01 00 00 45 85 ed 0f 84 41 01 00 00 41 83 fd 31
RSP: 0018:ffffc90003c1f840 EFLAGS: 00000807
RAX: 000000000000b7ca RBX: ffff8880465c1398 RCX: ffffffff93490310
RDX: 0000000000000002 RSI: 000000000000075a RDI: ffff888022ca0000
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1f47007 R12: 0000000000000000
R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881a3c1c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000000f000 CR3: 000000010e802000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 lock_acquire+0x120/0x360
 _raw_spin_lock_bh+0x36/0x50
 batadv_nc_purge_paths+0xe7/0x3b0
 batadv_nc_worker+0x369/0x610
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
