INFO: task syz.8.6755:22141 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.6755      state:D stack:25456 pid:22141 tgid:22140 ppid:21888  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17d9/0x56c0
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7bf/0x1550
 nfsd_nl_svc_export_set_reqs_doit+0x132/0x1450
 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: 0033:0x7f08e999ce59
RSP: 002b:00007f08ea7e3028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f08e9c15fa0 RCX: 00007f08e999ce59
RDX: 0000000024000004 RSI: 0000200000000640 RDI: 0000000000000006
RBP: 00007f08e9a32e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f08e9c16038 R14: 00007f08e9c15fa0 R15: 00007ffecfb52888
 </TASK>
INFO: lockdep is turned off.
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+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: 28620 Comm: syz.4.9454 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:kernel_text_address+0x1c/0xe0
Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 55 41 56 53 48 81 ff 00 00 00 81 0f 93 c0 48 81 ff a0 69 b2 8b 0f 92 c1 <bd> 01 00 00 00 84 c8 75 0c 48 89 fb e8 f3 d9 a3 ff 85 c0 74 0c 89
RSP: 0018:ffffc90007eb7578 EFLAGS: 00000287
RAX: 0000000000000001 RBX: ffffffff82220ec4 RCX: 0000000080000001
RDX: ffffc90007eb7601 RSI: ffffffff8c2a8d60 RDI: ffffffff82220ec4
RBP: ffffc90007eb7650 R08: ffffc90007eb7968 R09: 0000000000000000
R10: ffffc90007eb7618 R11: fffff52000fd6ec5 R12: ffff88816f1dbb80
R13: 1ffff1102de3b82f R14: dffffc0000000000 R15: 1ffff92000fd6ec2
FS:  00007faefae006c0(0000) GS:ffff8882a9251000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c27b492 CR3: 000000016f2f6000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 __kernel_text_address+0xd/0x30
 unwind_get_return_address+0x4d/0x90
 arch_stack_walk+0xfb/0x150
 stack_trace_save+0xa9/0x100
 save_stack+0x122/0x230
 __reset_page_owner+0x71/0x1f0
 free_pages_prepare+0x961/0xa60
 __free_contig_range_common+0x174/0x340
 free_pages_bulk+0x48/0x120
 vfree+0x224/0x4a0
 kcov_close+0x28/0x50
 __fput+0x418/0xa50
 task_work_run+0x1d9/0x270
 do_exit+0x73a/0x2360
 do_group_exit+0x22d/0x2f0
 get_signal+0x121b/0x12c0
 arch_do_signal_or_restart+0xbb/0x860
 exit_to_user_mode_loop+0x104/0x730
 do_syscall_64+0x353/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7faef9f5d68e
Code: Unable to access opcode bytes at 0x7faef9f5d664.
RSP: 002b:00007faefadfff58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: fffffffffffffdfc RBX: 00007faefae006c0 RCX: 00007faef9f5d68e
RDX: 00007faefadfffb0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007faefa032e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007faefa216038 R14: 00007faefa215fa0 R15: 00007ffd1e43e088
 </TASK>
