INFO: task syz.0.5890:29338 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.5890      state:D stack:23528 pid:29338 tgid:29337 ppid:5625   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x1821/0x5740
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7f7/0x1550
 nfsd_nl_listener_set_doit+0x141/0x1670
 genl_family_rcv_msg_doit+0x22a/0x330
 genl_rcv_msg+0x61c/0x7a0
 netlink_rcv_skb+0x232/0x4b0
 genl_rcv+0x28/0x40
 netlink_unicast+0x75c/0x8e0
 netlink_sendmsg+0x813/0xb40
 ____sys_sendmsg+0x972/0x9f0
 ___sys_sendmsg+0x2a5/0x360
 __x64_sys_sendmsg+0x1bd/0x2a0
 do_syscall_64+0x174/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc9c559ce59
RSP: 002b:00007fc9c64c0028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fc9c5815fa0 RCX: 00007fc9c559ce59
RDX: 0000000000000000 RSI: 00002000000001c0 RDI: 000000000000000b
RBP: 00007fc9c5632d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc9c5816038 R14: 00007fc9c5815fa0 R15: 00007ffcbe4aed38
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e95cc20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5448:
 #0: ffff88810d6780a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900034732e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0
3 locks held by kworker/u8:2/5651:
 #0: ffff888109b56140 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860
 #1: ffffc900047afc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860
 #2: ffffffff8fdc9d00 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x11e/0x14c0
3 locks held by kworker/1:5/5680:
 #0: ffff88810006b140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860
 #1: ffffc9000497fc40 (rx_mode_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860
 #2: ffffffff8fdc9d00 (rtnl_mutex){+.+.}-{4:4}, at: netdev_rx_mode_work+0x19/0x3c0
3 locks held by kworker/u9:8/7174:
 #0: ffff8881000ac140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860
 #1: ffffc9000660fc40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860
 #2: ffffffff8fdc9d00 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60
2 locks held by syz.2.5616/28257:
 #0: ffffffff8fe3a248 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8ec8b2c0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x141/0x1670
2 locks held by syz.0.5890/29338:
 #0: ffffffff8fe3a248 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8ec8b2c0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x141/0x1670
2 locks held by syz.3.6965/1261:
 #0: ffffffff8fe3a248 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8ec8b2c0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_version_get_doit+0x181/0xcd0
2 locks held by syz.4.7111/1895:
 #0: ffffffff8fdbafe8 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4f7/0x730
 #1: ffffffff8fdc9d00 (rtnl_mutex){+.+.}-{4:4}, at: cfg80211_pernet_exit+0x19/0x120
2 locks held by syz.1.7117/1913:
 #0: ffffffff8fdc9d00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0
 #1: ffffffff8e962f28 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770
2 locks held by syz.1.7117/1917:
 #0: ffffffff9030d7a0 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250
 #1: ffffffff8fdc9d00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0
2 locks held by syz.1.7117/1919:
 #0: ffffffff90324b68 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250
 #1: ffffffff8fdc9d00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0
1 lock held by syz.5.7118/1916:
 #0: ffffffff8fdc9d00 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0
2 locks held by syz.5.7118/1920:
 #0: ffffffff8fe3a248 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8fdc9d00 (rtnl_mutex){+.+.}-{4:4}, at: nl80211_pre_doit+0x5e/0x8a0
2 locks held by syz.5.7118/1921:
 #0: ffffffff8fe3a248 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8fdc9d00 (rtnl_mutex){+.+.}-{4:4}, at: nl80211_pre_doit+0x5e/0x8a0

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 34 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+0xfd3/0x1030
 kthread+0x389/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5981 Comm: kworker/u8:5 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_tt_purge
RIP: 0010:__lock_acquire+0x46/0x2cf0
Code: 24 e0 00 00 00 65 48 8b 05 ff a7 97 11 48 89 44 24 08 31 ed 83 3d c9 28 8f 0e 00 0f 84 ef 13 00 00 45 89 cf 49 89 f9 48 8b 07 <48> 3d 80 23 fd 93 0f 84 da 13 00 00 41 89 cd 41 89 d6 8b 0d a2 04
RSP: 0018:ffffc90006cf7858 EFLAGS: 00000002
RAX: ffffffff9a991740 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888115e69e98
RBP: 0000000000000000 R08: 0000000000000001 R09: ffff888115e69e98
R10: dffffc0000000000 R11: fffffbfff20613bf R12: 0000000000000000
R13: ffff888115e69e98 R14: 0000000000000001 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88818dc8b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005651445b7de0 CR3: 000000011103e000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lock_acquire+0x106/0x350
 _raw_spin_lock_bh+0x36/0x50
 batadv_tt_purge+0x11b/0x9e0
 process_scheduled_works+0xb5d/0x1860
 worker_thread+0xa53/0xfc0
 kthread+0x389/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
