INFO: task kworker/R-ipv6_:3251 blocked for more than 143 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/R-ipv6_ state:D
 stack:29320 pid:3251  tgid:3251  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue:  0x0 (ipv6_addrconf)
Call Trace:
 <TASK>
 __schedule+0x17b4/0x5680
 schedule+0x164/0x360
 rescuer_thread+0xfbc/0x1130
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Showing all locks held in the system:
1 lock held by kthreadd/2:
1 lock held by khungtaskd/34:
 #0: ffffffff8e95cda0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by kswapd1/90:
3 locks held by kworker/0:2/796:
 #0: ffff88810006b140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860
 #1: ffffc900048c7c40 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860
 #2: ffffffff8fdd03c0 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20
3 locks held by kworker/u11:1/5000:
 #0: ffff88801f7d2940 ((wq_completion)hci3){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860
 #1: ffffc9002241fc40 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860
 #2: ffff888119034ea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_cmd_sync_work+0x1d3/0x400
1 lock held by klogd/5048:
5 locks held by udevd/5059:
3 locks held by dhcpcd/5355:
2 locks held by getty/5437:
 #0: ffff888115fa80a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000346b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0
2 locks held by syz-executor/5600:
3 locks held by kworker/0:5/5689:
 #0: ffff88810006b140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860
 #1: ffffc900064a7c40 ((work_completion)(&m->mpeg_thread)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860
 #2: ffffffff8eaa1250 (remove_cache_srcu){.+.+}-{0:0}, at: srcu_read_lock+0x27/0x60
5 locks held by kworker/u8:0/14741:
4 locks held by kworker/u8:7/15349:
4 locks held by kworker/u8:8/15350:
5 locks held by kworker/u8:9/15351:
4 locks held by kworker/u8:11/15353:
2 locks held by syz-executor/7329:
4 locks held by kworker/0:10/11068:
1 lock held by syz.4.13857/11175:
2 locks held by syz-executor/11192:

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

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: 14741 Comm: kworker/u8:0 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#4/0 rds_connect_worker
RIP: 0010:check_preemption_disabled+0x22/0xe0
Code: 90 90 90 90 90 90 90 90 55 41 57 41 56 53 65 8b 05 b7 bf 90 07 65 8b 0d ac bf 90 07 f7 c1 ff ff ff 7f 74 0c 5b 41 5e 41 5f 5d <e9> 49 d9 02 00 cc 9c 59 f7 c1 00 02 00 00 74 ea 65 4c 8b 3d 5e bf
RSP: 0018:ffffc90003af74c0 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000046
RDX: 00000000b8ec9bdb RSI: ffffffff8e21c2f0 RDI: ffffffff8c28b4e0
RBP: ffffffff823ca8a2 R08: ffffffff823ca8a2 R09: ffffffff8e95cda0
R10: dffffc0000000000 R11: fffff940002193e7 R12: 0000000000000002
R13: ffffffff8e95cda0 R14: 0000000000000000 R15: 0000000000000246
FS:  0000000000000000(0000) GS:ffff88818dc90000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f713a948700 CR3: 0000000118ca4000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lock_acquire+0x116/0x350
 page_ext_get+0x3e/0x2e0
 __reset_page_owner+0x28/0x1f0
 __free_frozen_pages+0xbbe/0xd20
 __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+0x995/0xd50
 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>
