INFO: task syz.2.338:6756 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.338       state:D stack:27656 pid:6756  tgid:6755  ppid:5849   task_flags:0x400040 flags:0x00080003
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7e6/0x1350
 rtnetlink_rcv_msg+0x71c/0xb70
 unmap_vmas+0x399/0x580
 exit_mmap+0x240/0xb40
 __mmput+0x118/0x430
 </TASK>

Showing all locks held in the system:
5 locks held by kworker/1:0/24:
1 lock held by khungtaskd/34:
 #0: ffffffff8e33d320 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
3 locks held by kworker/u10:8/3617:
 #0: ffff88801ac89948 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc9002072fba0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f73f3c8 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60
1 lock held by klogd/5289:
2 locks held by udevd/5300:
 #0: ffff88813663a018 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140
 #1: ffff888136624048 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880
4 locks held by dhcpcd/5596:
2 locks held by getty/5678:
 #0: ffff88810f7d30a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900029032f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
1 lock held by syz-executor/5786:
 #0: ffff888028858688 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1a3/0x450
5 locks held by syz-executor/5848:
 #0: ffff888024124dc8 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x212/0x510
 #1: ffff8880241240b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x66a/0x1330
 #2: ffffffff8f8a4448 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xa1/0x230
 #3: ffff88810aaef338 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x70/0x680
 #4: ffffffff8e342db8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730
3 locks held by kworker/0:3/5854:
 #0: ffff88801ac75948 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc9000367fba0 (reg_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8f73f3c8 (rtnl_mutex){+.+.}-{4:4}, at: reg_todo+0x1c/0x890
1 lock held by syz-executor/5857:
 #0: ffffffff8f73f3c8 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0
1 lock held by syz-executor/6768:
2 locks held by dhcpcd/6773:
 #0: ffff888020268258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x33/0xd30
 #1: ffffffff8e342db8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730
1 lock held by dhcpcd/6775:
 #0: ffff88802026a258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x33/0xd30
1 lock held by dhcpcd/6776:
 #0: ffff888030ce2258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x33/0xd30

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

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+0xf60/0xfa0
 kthread+0x711/0x8a0
 ret_from_fork+0x4bc/0x870
 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: 6756 Comm: syz.2.338 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:__free_frozen_pages+0x4f1/0xd30
Code: c4 0b 83 fd 40 0f 83 9a 03 00 00 4c 89 e7 4c 89 ee e8 13 9c bf 02 83 fd 20 0f 83 a6 03 00 00 0f 1f 44 00 00 44 0f b6 64 24 2c <48> 89 df 89 ee 44 89 e2 e8 b2 0a 0e 00 45 84 e4 74 2b 44 89 7c 24
RSP: 0018:ffffc90004fef8b8 EFLAGS: 00000283
RAX: e16452e09bc7e600 RBX: ffffea0000b0d500 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8db9fb67 RDI: 00000000ffffffff
RBP: 0000000000000000 R08: ffffffff8fc35877 R09: 1ffffffff1f86b0e
R10: dffffc0000000000 R11: fffffbfff1f86b0f R12: 0000000000000000
R13: 0000000000001000 R14: 0000000000000001 R15: 0000000000000000
FS:  00007f340b5396c0(0000) GS:ffff8880b83fc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd059bd6038 CR3: 000000010a5e0000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 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+0x1285/0x1340
 arch_do_signal_or_restart+0xa0/0x790
 exit_to_user_mode_loop+0x72/0x130
 do_syscall_64+0x2bd/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f340a78ec29
Code: Unable to access opcode bytes at 0x7f340a78ebff.
RSP: 002b:00007f340b539038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: 0000000000000028 RBX: 00007f340a9d5fa0 RCX: 00007f340a78ec29
RDX: 0000000000000802 RSI: 00002000000003c0 RDI: 0000000000000003
RBP: 00007f340a811e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f340a9d6038 R14: 00007f340a9d5fa0 R15: 00007ffcdf46be18
 </TASK>
