INFO: task syz.2.817:8799 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.817       state:D stack:25416 pid:8799  tgid:8798  ppid:5605   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17d9/0x56c0
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7bf/0x1550
 nfsd_nl_listener_set_doit+0x135/0x1750
 genl_family_rcv_msg_doit+0x233/0x340
 genl_rcv_msg+0x614/0x7a0
 netlink_rcv_skb+0x226/0x4a0
 genl_rcv+0x28/0x40
 netlink_unicast+0x7bb/0x940
 netlink_sendmsg+0x813/0xb40
 sock_sendmsg_nosec+0x13a/0x180
 ____sys_sendmsg+0x54e/0x850
 ___sys_sendmsg+0x2a5/0x360
 __x64_sys_sendmsg+0x1b1/0x290
 do_syscall_64+0x174/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa2da59de99
RSP: 002b:00007fa2db4e7028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fa2da825fa0 RCX: 00007fa2da59de99
RDX: 0000000020040080 RSI: 0000200000000100 RDI: 0000000000000007
RBP: 00007fa2da633eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa2da826038 R14: 00007fa2da825fa0 R15: 00007fffbd73c178
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/0:0/9:
 #0: ffff88810006b140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #1: ffffc900000e7c40 (xfrm_state_gc_work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
1 lock held by khungtaskd/34:
 #0: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
4 locks held by kworker/u9:8/1116:
 #0: ffff8881000ac140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #1: ffffc90007217c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #2: ffffffff9002d500 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60
 #3: ffffffff8eb5ff68 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770
2 locks held by getty/5434:
 #0: ffff88816d9670a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900034732e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360
4 locks held by kworker/u8:3/5662:
 #0: ffff8881012d5940 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #1: ffffc9000659fc40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #2: ffffffff9001e948 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf5/0x810
 #3: ffffffff8eb5fe38 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530
3 locks held by kworker/1:15/7943:
 #0: ffff88810006b140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #1: ffffc9000354fc40 (netdev_work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #2: ffffffff9002d500 (rtnl_mutex){+.+.}-{4:4}, at: netdev_work_proc+0x6f/0x770
2 locks held by syz.1.744/8565:
 #0: ffffffff9009dee8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8ee8e5a0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x135/0x1750
2 locks held by syz.2.817/8799:
 #0: ffffffff9009dee8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8ee8e5a0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x135/0x1750
3 locks held by kworker/0:17/9013:
 #0: ffff88810006b140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #1: ffffc90008007c40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #2: ffff8881bce5e250 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x1fd/0x3b0
1 lock held by syz.4.2046/13568:
 #0: ffffffff9002d500 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0
2 locks held by syz.0.2048/13576:
 #0: ffffffff90595520 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250
 #1: ffffffff9002d500 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0xc10/0x1c30
2 locks held by syz.0.2048/13580:
 #0: ffffffff90594000 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250
 #1: ffffffff9002d500 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0xc10/0x1c30

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

NMI backtrace for cpu 0
CPU: 0 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/0x380
 sys_info+0x135/0x170
 watchdog+0xfd7/0x1030
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 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: 5037 Comm: syslogd 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:__mutex_unlock_slowpath+0x2f/0x900
Code: 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48 81 ec c0 00 00 00 48 89 fb 65 48 8b 05 59 8f 9a 07 48 89 84 24 a0 00 00 00 <49> be 00 00 00 00 00 fc ff df 48 c7 44 24 40 b3 8a b5 41 48 c7 44
RSP: 0018:ffffc900078278c0 EFLAGS: 00000286
RAX: 904d6696e9028d00 RBX: ffff888114f9b010 RCX: 0000000000000046
RDX: 0000000000000006 RSI: ffffffff8a73be3b RDI: ffff888114f9b010
RBP: ffffc900078279b0 R08: ffffffff90578f37 R09: 1ffffffff20af1e6
R10: dffffc0000000000 R11: fffffbfff20af1e7 R12: ffff8881be6f3b00
R13: dffffc0000000000 R14: 1ffff92000f04f44 R15: ffff888114f9aa80
FS:  00007f9e86840380(0000) GS:ffff8882a8f54000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fba6a581ff8 CR3: 0000000114d0a000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 __unix_dgram_recvmsg+0x9eb/0xd70
 sock_recvmsg+0x196/0x1e0
 sock_read_iter+0x22a/0x2f0
 vfs_read+0x595/0xa80
 ksys_read+0x150/0x270
 do_syscall_64+0x174/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9e86994b6a
Code: 00 3d 00 00 41 00 75 0d 50 48 8d 3d 2d 08 0a 00 e8 ea 7d 01 00 31 c0 e9 07 ff ff ff 64 8b 04 25 18 00 00 00 85 c0 75 1b 0f 05 <48> 3d 00 f0 ff ff 76 6c 48 8b 15 8f a2 0d 00 f7 d8 64 89 02 48 83
RSP: 002b:00007fff27ffb518 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f9e86994b6a
RDX: 00000000000000ff RSI: 0000561039459950 RDI: 0000000000000000
RBP: 0000561039459910 R08: 000000000000c000 R09: 0000000000000000
R10: 0000561039459f00 R11: 0000000000000246 R12: 000056103945999c
R13: 0000561039459950 R14: 0000000000000000 R15: 00007f9e86b79a80
 </TASK>
