INFO: task syz.3.721:8527 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.721       state:D stack:26024 pid:8527  tgid:8526  ppid:8451   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_get_doit+0x10a/0x5e0
 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: 0033:0x7fbf8478ebe9
RSP: 002b:00007fbf856d6038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fbf849c5fa0 RCX: 00007fbf8478ebe9
RDX: 0000000000000010 RSI: 0000200000001540 RDI: 0000000000000004
RBP: 00007fbf84811e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbf849c6038 R14: 00007fbf849c5fa0 R15: 00007fff9faf6d18
 </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: 5847 Comm: syz-executor 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:unwind_next_frame+0x2ab/0x2390
Code: 00 45 39 e8 48 bd 00 00 00 00 00 fc ff df 0f 84 03 02 00 00 4a 8d 14 ad f0 84 b1 8f 45 29 e8 4a 8d 1c 82 48 83 c3 fc 49 89 d5 <48> 39 da 0f 86 1c 10 00 00 49 29 d5 e9 80 00 00 00 31 db e9 eb 16
RSP: 0018:ffffc90003b6f538 EFLAGS: 00000293
RAX: ffffffff90345716 RBX: ffffffff8fb80a40 RCX: 3c15224c7b7cdf00
RDX: ffffffff8fb80a40 RSI: ffffffff90345710 RDI: ffffffff8be33620
RBP: dffffc0000000000 R08: 0000000000000001 R09: 0000000000000000
R10: ffffc90003b6f658 R11: ffffffff81ac3810 R12: ffffffff81876d95
R13: ffffffff8fb80a40 R14: ffffc90003b6f608 R15: 000000000000876d
FS:  00005555752e9500(0000) GS:ffff8881a3c18000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2742b84fc8 CR3: 000000000df36000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 arch_stack_walk+0x11c/0x150
 stack_trace_save+0x9c/0xe0
 save_stack+0xf5/0x1f0
 __reset_page_owner+0x71/0x1f0
 __free_frozen_pages+0xbc4/0xd30
 vfree+0x25a/0x400
 kcov_close+0x28/0x50
 __fput+0x44c/0xa70
 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: 0033:0x7f2741dc14a5
Code: Unable to access opcode bytes at 0x7f2741dc147b.
RSP: 002b:00007ffe1db3dcd0 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6
RAX: 0000000000000000 RBX: 0000000000000b04 RCX: 00007f2741dc14a5
RDX: 00007ffe1db3dd10 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffe1db3dd7c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000001388
R13: 00000000000927c0 R14: 0000000000040c85 R15: 00007ffe1db3ddd0
 </TASK>
