INFO: task kworker/u8:7:14504 blocked for more than 149 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:7    state:D stack:26104 pid:14504 tgid:14504 ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: ipv6_addrconf addrconf_verify_work
Call Trace:
 <TASK>
 __schedule+0x1821/0x5740
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7f7/0x1550
 addrconf_verify_work+0x19/0x30
 process_scheduled_works+0xb5d/0x1860
 worker_thread+0xa53/0xfc0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Showing all locks held in the system:
4 locks held by kworker/0:0/9:
 #0: ffff888100069d40 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860
 #1: ffffc900000e7c40 ((reg_check_chans).work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860
 #2: ffffffff8fdcff00 (rtnl_mutex){+.+.}-{4:4}, at: reg_check_chans_work+0xab/0x1090
 #3: ffff8880216c0780 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: reg_check_chans_work+0x197/0x1090
3 locks held by kworker/1:1/31:
 #0: ffff88810006b140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860
 #1: ffffc90000a67c40 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860
 #2: ffffffff8fdcff00 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20
1 lock held by khungtaskd/34:
 #0: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
1 lock held by kcompactd0/38:
2 locks held by kworker/0:2/917:
3 locks held by syslogd/5042:
1 lock held by klogd/5049:
2 locks held by udevd/5060:
3 locks held by dhcpcd/5356:
5 locks held by dhcpcd/5357:
2 locks held by getty/5445:
 #0: ffff8881136480a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900034732e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0
6 locks held by kworker/u8:2/5507:
 #0: ffff8881012b5940 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860
 #1: ffffc900069a7c40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860
 #2: ffffffff8fdc1228 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf4/0x800
 #3: ffff888104318128 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x129/0x420
 #4: ffff88810431f258 (&devlink->lock_key#4){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x142/0x420
 #5: ffffffff8e963068 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770
1 lock held by syz-executor/5596:
4 locks held by kworker/0:3/5669:
1 lock held by syz.1.766/7773:
 #0: ffffffff8fdcff00 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0
3 locks held by syz-executor/8938:
1 lock held by syz-executor/13522:
 #0: ffffffff8fdcff00 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0
2 locks held by syz-executor/14507:
2 locks held by syz-executor/14514:

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 34 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
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+0xfd3/0x1030
 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: 5823 Comm: kworker/u8:4 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: krds_cp_wq#5/0 rds_connect_worker
RIP: 0010:rcu_lockdep_current_cpu_online+0x6a/0x120
Code: 00 00 49 be 00 00 00 00 00 fc ff df 48 8d 1c dd 90 57 26 8e 48 89 d8 48 c1 e8 03 42 80 3c 30 00 74 08 48 89 df e8 c6 df 85 00 <48> 8b 03 48 8d 98 80 ee 3a 93 48 8d b8 a8 ee 3a 93 48 89 f8 48 c1
RSP: 0018:ffffc90006ec7510 EFLAGS: 00000246
RAX: 1ffffffff1c4caf2 RBX: ffffffff8e265790 RCX: 0000000080000001
RDX: 0000000000000000 RSI: ffffffff8c28aec0 RDI: ffffffff8c28ae80
RBP: dffffc0000000000 R08: ffffffff823c8b6a R09: ffffffff8e95cd60
R10: dffffc0000000000 R11: ffffed100464f040 R12: 000000000002d819
R13: dffffc0000000000 R14: dffffc0000000000 R15: 0000000000001000
FS:  0000000000000000(0000) GS:ffff88818dc8d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f05e094d008 CR3: 00000001149de000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 rcu_read_lock_held+0x1e/0x50
 page_ext_lookup+0xe7/0x180
 __page_table_check_zero+0x135/0x3e0
 __free_frozen_pages+0xbd7/0xd30
 __slab_free+0x274/0x2c0
 qlist_free_all+0x99/0x100
 kasan_quarantine_reduce+0x148/0x160
 __kasan_slab_alloc+0x22/0x80
 kmem_cache_alloc_noprof+0x2bc/0x650
 security_inode_alloc+0x39/0x310
 inode_init_always_gfp+0x9c8/0xda0
 alloc_inode+0x82/0x1b0
 __sock_create+0x12d/0x9d0
 rds_tcp_conn_path_connect+0x2d7/0x930
 rds_connect_worker+0x1d8/0x290
 process_scheduled_works+0xb5d/0x1860
 worker_thread+0xa53/0xfc0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
