INFO: task kworker/0:4:6184 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:4     state:D stack:22632 pid:6184  tgid:6184  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: events_power_efficient reg_check_chans_work
Call Trace:
 <TASK>
 __schedule+0x15dd/0x52d0
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7fe/0x1300
 reg_check_chans_work+0x171/0xfe0
 process_scheduled_works+0xb6e/0x18c0
 worker_thread+0xa53/0xfc0
 kthread+0x388/0x470
 ret_from_fork+0x51e/0xb90
 ret_from_fork_asm+0x1a/0x30
 </TASK>
INFO: task kworker/u8:4:7049 blocked for more than 154 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:4    state:D stack:23904 pid:7049  tgid:7049  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: ipv6_addrconf addrconf_verify_work
Call Trace:
 <TASK>
 __schedule+0x15dd/0x52d0
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7fe/0x1300
 addrconf_verify_work+0x19/0x30
 process_scheduled_works+0xb6e/0x18c0
 worker_thread+0xa53/0xfc0
 kthread+0x388/0x470
 ret_from_fork+0x51e/0xb90
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Showing all locks held in the system:
4 locks held by kworker/1:1/31:
1 lock held by khungtaskd/35:
 #0: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
3 locks held by kworker/u10:2/68:
 #0: ffff8881000ac148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0
 #1: ffffc900017afc40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0
 #2: ffffffff8fbd1648 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60
2 locks held by klogd/5247:
3 locks held by udevd/5258:
2 locks held by dhcpcd/5553:
3 locks held by dhcpcd/5554:
2 locks held by getty/5635:
 #0: ffff88816bf750a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000356b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0
1 lock held by syz-executor/6131:
 #0: ffffffff8fbd1648 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0
2 locks held by kworker/0:5/6193:
3 locks held by kworker/1:5/6198:
 #0: ffff88810006b148 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0
 #1: ffffc900064bfc40 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0
 #2: ffffffff8fbd1648 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20
1 lock held by syz-executor/7046:
 #0: ffffffff8fbd1648 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0
3 locks held by kworker/u8:4/7049:
 #0: ffff888112440948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0
 #1: ffffc90002957c40 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0
 #2: ffffffff8fbd1648 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_verify_work+0x19/0x30
1 lock held by udevd/7805:
1 lock held by syz.0.1009/8007:
 #0: ffffffff8fbd1648 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0
3 locks held by syz-executor/8015:
2 locks held by syz-executor/8016:
2 locks held by dhcpcd/8017:
 #0: ffff88816a73b208 (&sb->s_type->i_mutex_key#14){+.+.}-{4:4}, at: sock_close+0x9b/0x240
 #1: ffffffff8e7648b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770

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

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/0x300
 sys_info+0x135/0x170
 watchdog+0xfd9/0x1030
 kthread+0x388/0x470
 ret_from_fork+0x51e/0xb90
 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: 8014 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+0x1397/0x23c0
Code: b6 44 2d 00 84 c0 0f 85 02 0e 00 00 c6 03 00 4c 8b 64 24 48 4c 8b 7c 24 28 48 8b 44 24 40 0f b6 04 28 84 c0 0f 85 6c 0b 00 00 <41> 0f b6 04 2f 84 c0 0f 85 83 0b 00 00 0f b7 32 c1 ee 04 83 e6 0f
RSP: 0018:ffffc9000654ed58 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffc9000654ee60 RCX: 0000000000000000
RDX: ffffffff90b365f8 RSI: 0000000000000000 RDI: ffffc9000654ee88
RBP: dffffc0000000000 R08: ffffc9000654ee87 R09: 0000000000000000
R10: ffffc9000654ee78 R11: fffff52000ca9dd1 R12: ffffc9000654ee78
R13: 1ffff92000ca9dc7 R14: ffffc9000654ee28 R15: 1ffffffff2166cbf
FS:  0000555558bb3500(0000) GS:ffff88818de62000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffcf8a70ff8 CR3: 000000016c9a6000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 arch_stack_walk+0x11b/0x150
 stack_trace_save+0xa9/0x100
 save_stack+0x122/0x230
 __reset_page_owner+0x71/0x1f0
 __free_frozen_pages+0xbc7/0xd30
 __slab_free+0x263/0x2b0
 qlist_free_all+0x99/0x100
 kasan_quarantine_reduce+0x148/0x160
 __kasan_kmalloc+0x22/0xb0
 __kmalloc_noprof+0x35c/0x760
 ext4_ext_remove_space+0x383/0x4280
 ext4_ext_truncate+0x17e/0x2f0
 ext4_truncate+0xb63/0x13b0
 ext4_evict_inode+0x863/0xeb0
 evict+0x61e/0xb10
 __dentry_kill+0x1a2/0x5e0
 finish_dput+0xc9/0x480
 __fput+0x691/0xa70
 task_work_run+0x1d9/0x270
 do_exit+0x70f/0x22c0
 do_group_exit+0x21b/0x2d0
 get_signal+0x1284/0x1330
 arch_do_signal_or_restart+0xbc/0x830
 exit_to_user_mode_loop+0x86/0x480
 do_syscall_64+0x32d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4c5ab9c4ab
Code: Unable to access opcode bytes at 0x7f4c5ab9c481.
RSP: 002b:00007fffbf6d1f80 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 0000000000080000 RCX: 00007f4c5ab9c4ab
RDX: 0000000000080000 RSI: ffffffff80086301 RDI: 00000000000000da
RBP: 00007f4c5ae16218 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000003 R14: 00007fffbf6d2238 R15: 0000000000000000
 </TASK>
