INFO: task syz.2.1008:9469 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.1008      state:D stack:25960 pid:9469  tgid:9467  ppid:5849   task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7e6/0x1350
 nfsd_nl_listener_set_doit+0x137/0x1690
 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: 0033:0x7f946098ebe9
RSP: 002b:00007f9461736038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f9460bc5fa0 RCX: 00007f946098ebe9
RDX: 0000000000000000 RSI: 0000200000000040 RDI: 0000000000000006
RBP: 00007f9460a11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9460bc6038 R14: 00007f9460bc5fa0 R15: 00007ffd819aeb88
 </TASK>
INFO: lockdep is turned off.
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+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: 17010 Comm: syz.6.3095 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:stack_trace_consume_entry+0xf3/0x280
Code: 8b 74 24 08 48 8b 1f 45 8d 79 01 0f b6 44 15 00 84 c0 0f 85 3a 01 00 00 45 89 38 4e 8d 3c cb 4c 89 f8 48 c1 e8 03 80 3c 10 00 <74> 1a 4c 89 ff 48 89 f3 49 89 d4 4c 89 c5 e8 da de 76 00 49 89 e8
RSP: 0018:ffffc9000835f1f8 EFLAGS: 00000246
RAX: 1ffff9200106be7d RBX: ffffc9000835f390 RCX: 0b59f3377d326c00
RDX: dffffc0000000000 RSI: ffffffff82347a4c RDI: ffffc9000835f300
RBP: 1ffff9200106be62 R08: ffffc9000835f310 R09: 000000000000000b
R10: ffffc9000835f298 R11: ffffffff81ac3810 R12: 0000000000000000
R13: 1ffff9200106be61 R14: ffffc9000835f308 R15: ffffc9000835f3e8
FS:  00007f52a92476c0(0000) GS:ffff8881a3c18000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd816f0c000 CR3: 000000001fc5a000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 arch_stack_walk+0x110/0x150
 stack_trace_save+0x9c/0xe0
 kasan_save_stack+0x3e/0x60
 kasan_record_aux_stack+0xbd/0xd0
 call_rcu+0x157/0x9c0
 __dentry_kill+0x4d2/0x660
 shrink_kill+0xa9/0x2c0
 shrink_dentry_list+0x2e0/0x5e0
 shrink_dcache_parent+0xa1/0x2c0
 do_one_tree+0x23/0xe0
 shrink_dcache_for_umount+0xa0/0x170
 generic_shutdown_super+0x67/0x2c0
 kill_litter_super+0x76/0xb0
 deactivate_locked_super+0xbc/0x130
 cleanup_mnt+0x425/0x4c0
 task_work_run+0x1d4/0x260
 do_exit+0x6b5/0x2300
 do_group_exit+0x21c/0x2d0
 get_signal+0x1286/0x1340
 arch_do_signal_or_restart+0x9a/0x750
 exit_to_user_mode_loop+0x75/0x110
 do_syscall_64+0x2bd/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f52a838ebe9
Code: Unable to access opcode bytes at 0x7f52a838ebbf.
RSP: 002b:00007f52a92470e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f52a85c6098 RCX: 00007f52a838ebe9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f52a85c6098
RBP: 00007f52a85c6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f52a85c6128 R14: 00007ffc0347ed30 R15: 00007ffc0347ee18
 </TASK>
