INFO: task syz.2.17436:9649 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.17436     state:D stack:24344 pid:9649  tgid:9648  ppid:8580   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_svc_export_get_reqs_dumpit+0xf7/0xc40
 genl_dumpit+0x10b/0x1b0
 netlink_dump+0x711/0xee0
 __netlink_dump_start+0x589/0x7b0
 genl_family_rcv_msg_dumpit+0x213/0x310
 genl_rcv_msg+0x5e1/0x7a0
 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: 0033:0x7f3cfb59ce59
RSP: 002b:00007f3cfc3ed028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f3cfb815fa0 RCX: 00007f3cfb59ce59
RDX: 00000000040088c0 RSI: 0000200000000000 RDI: 000000000000000a
RBP: 00007f3cfb632e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3cfb816038 R14: 00007f3cfb815fa0 R15: 00007ffe07f15a38
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/35:
 #0: ffffffff8e959c60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5440:
 #0: ffff888110d7e0a0 (&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
2 locks held by syz.4.17130/8372:
 #0: ffffffff8fe5bae8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8ec8eaa0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x2b9/0xc30
3 locks held by syz.2.17436/9649:
 #0: ffffffff8fe5bae8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffff8881a469d6e8 (nlk_cb_mutex-GENERIC){+.+.}-{4:4}, at: __netlink_dump_start+0xf4/0x7b0
 #2: ffffffff8ec8eaa0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_svc_export_get_reqs_dumpit+0xf7/0xc40
3 locks held by syz.9.17954/11880:
 #0: ffffffff8fe5bae8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffff88816ad856e8 (nlk_cb_mutex-GENERIC){+.+.}-{4:4}, at: __netlink_dump_start+0xf4/0x7b0
 #2: ffffffff8ec8eaa0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_svc_export_get_reqs_dumpit+0xf7/0xc40
2 locks held by syz.7.18115/12629:
 #0: ffffffff8fe5bae8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8ec8eaa0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_version_set_doit+0xcd/0x7a0
1 lock held by syz.0.18159/12790:
 #0: ffffffff8e9cbf60 (event_mutex){+.+.}-{4:4}, at: perf_trace_destroy+0x2e/0x150
1 lock held by syz.0.18159/12791:
 #0: ffffffff9a9b5960 (nfnl_subsys_ipset){+.+.}-{4:4}, at: call_ad+0x266/0xb50

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

NMI backtrace for cpu 1
CPU: 1 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 12791 Comm: syz.0.18159 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:__pi___x86_indirect_thunk_r11+0x0/0x20
Code: 00 00 00 0f 1f 80 00 00 00 00 e8 01 00 00 00 cc 4c 89 14 24 e9 d1 0a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 <e8> 01 00 00 00 cc 4c 89 1c 24 c3 cc cc cc cc 66 2e 0f 1f 84 00 00
RSP: 0018:ffffc9000436e620 EFLAGS: 00000282
RAX: ffffffff82286eb5 RBX: ffffc9000436e6e0 RCX: 0000000000000200
RDX: 0000000000000001 RSI: ffffffff82286eb5 RDI: ffffc9000436e6e0
RBP: ffffc9000436e6b0 R08: ffffc9000436e9b0 R09: 0000000000000000
R10: ffffc9000436e678 R11: ffffffff81b16af0 R12: ffff8881206a9dc0
R13: ffffffff82286ced R14: ffffffff81b16af0 R15: ffffc9000436e628
FS:  00007fca8484e6c0(0000) GS:ffff88818dc24000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055fb44f74000 CR3: 00000001190cc000 CR4: 00000000000006f0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 </TASK>
