INFO: task syz.2.1288:10492 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.1288      state:D stack:26064 pid:10492 tgid:10491 ppid:5848   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: 0033:0x7fce8798ec29
RSP: 002b:00007fce85bf6038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fce87bd5fa0 RCX: 00007fce8798ec29
RDX: 0000000000008000 RSI: 0000200000006e40 RDI: 0000000000000009
RBP: 00007fce87a11e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fce87bd6038 R14: 00007fce87bd5fa0 R15: 00007fff782d95f8
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_trace/31:
 #0: ffffffff8e13ae50 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{4:4}, at: rcu_tasks_one_gp+0xaf9/0xdf0
1 lock held by khungtaskd/34:
 #0: ffffffff8e13a120 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5677:
 #0: ffff8880247690a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900029062f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
2 locks held by syz.1.661/8196:
 #0: ffffffff8f5a0270 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8e419548 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x2cb/0x960
2 locks held by syz.2.1288/10492:
 #0: ffffffff8f5a0270 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8e419548 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_get_doit+0x10a/0x5e0
2 locks held by syz.0.2396/14271:
 #0: ffffffff8f5a0270 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffffffff8e419548 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x2cb/0x960
1 lock held by syz.5.2553/14833:
 #0: ffffffff8e19d6c8 (event_mutex){+.+.}-{4:4}, at: perf_trace_destroy+0x2e/0x150
1 lock held by syz.7.2555/14840:
 #0: ffff888024646d60 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock_killable+0x1d/0x70
4 locks held by syz.7.2555/14841:
2 locks held by syz.6.2558/14847:
 #0: ffffffff8e19d6c8 (event_mutex){+.+.}-{4:4}, at: perf_trace_destroy+0x2e/0x150
 #1: ffffffff8e13fbb8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730

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

NMI backtrace for cpu 1
CPU: 1 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+0x439/0x7d0
 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: 14841 Comm: syz.7.2555 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:its_return_thunk+0x0/0x10
Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc <c3> cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 e9 6b c2 b5 f5 cc
RSP: 0018:ffffc900000073a8 EFLAGS: 00000086
RAX: 0000000000000001 RBX: 0000000000000005 RCX: 0eaf808001e65500
RDX: 0000000000000001 RSI: ffff88811514c538 RDI: ffff88811514b980
RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff81ef476f
R10: dffffc0000000000 R11: ffffffff81ef46e0 R12: 0000000000004008
R13: ffff88811514c470 R14: ffff88811514c538 R15: 0ac0d5affe09d4ff
FS:  00007fb99bbf66c0(0000) GS:ffff8880b8612000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555558f44608 CR3: 0000000048074000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 __lock_acquire+0xab9/0xd20
 lock_acquire+0x120/0x360
 perf_event_output_forward+0xb0/0x430
 __perf_event_overflow+0x830/0xe40
 perf_swevent_event+0x4f8/0x5e0
 perf_tp_event+0x4f6/0x1380
 perf_trace_run_bpf_submit+0xee/0x170
 perf_trace_preemptirq_template+0x280/0x340
 trace_irq_disable+0xee/0x110
 _raw_spin_lock_irq+0x7d/0xf0
 __run_timer_base+0x622/0x860
 run_timer_softirq+0xb7/0x180
 handle_softirqs+0x286/0x870
 __irq_exit_rcu+0xca/0x1f0
 irq_exit_rcu+0x9/0x30
 sysvec_apic_timer_interrupt+0xa6/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:debug_lockdep_rcu_enabled+0x0/0x40
Code: a6 8d 08 f6 90 0f 0b 90 90 90 eb c4 cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 31 c0 83 3d 57 e4 28 04 00 74 1e 83 3d 6a 14 29 04 00
RSP: 0018:ffffc90004d5f2f0 EFLAGS: 00000282
RAX: 0eaf808001e65500 RBX: ffffffff822ef9da RCX: 0eaf808001e65500
RDX: 0000000000000000 RSI: ffffffff8dbaa0c3 RDI: ffffffff8be34280
RBP: ffffc90004d5f630 R08: 0000000000000000 R09: ffffffff822ef9da
R10: dffffc0000000000 R11: fffff94000965f31 R12: dffffc0000000000
R13: 1ffffd4000965f33 R14: 000000000012cbe6 R15: ffff88805fffa8a0
 pfn_valid+0xdf/0x490
 page_table_check_clear+0x21/0x700
 unmap_page_range+0x3445/0x4370
 unmap_vmas+0x399/0x580
 exit_mmap+0x248/0xb50
 __mmput+0x118/0x430
 copy_mm+0x1f3/0x4b0
 copy_process+0x1706/0x3c00
 kernel_clone+0x21e/0x840
 __x64_sys_clone+0x18b/0x1e0
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb99d98ec29
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb99bbf5fe8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007fb99dbd5fa0 RCX: 00007fb99d98ec29
RDX: 0000000000000000 RSI: 0000000000009000 RDI: 0000000004021400
RBP: 00007fb99da11e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007fb99dbd6038 R14: 00007fb99dbd5fa0 R15: 00007ffe3fc1ab78
 </TASK>
