syzbot

INFO: task kworker/R-ipv6_:3153 blocked for more than 151 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/R-ipv6_ state:D stack:29544 pid:3153  ppid:2      flags:0x00004000
Workqueue: ipv6_addrconf addrconf_verify_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0x1553/0x45a0 kernel/sched/core.c:6700
 schedule+0xbd/0x170 kernel/sched/core.c:6774
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6833
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x6a9/0xcc0 kernel/locking/mutex.c:747
 addrconf_verify_work+0x19/0x30 net/ipv6/addrconf.c:4718
 process_one_work kernel/workqueue.c:2634 [inline]
 process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2711
 rescuer_thread+0x50b/0xbe0 kernel/workqueue.c:2888
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>

Showing all locks held in the system:
2 locks held by kthreadd/2:
1 lock held by kworker/R-rcu_g/4:
 #0: ffffffff8cfddba8 (wq_pool_attach_mutex){+.+.}-{3:3}, at: worker_detach_from_pool+0x4c/0x270 kernel/workqueue.c:2137
6 locks held by kworker/R-netns/7:
 #0: ffff888017c73938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #0: ffff888017c73938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2711
 #1: ffffc900000c7d20 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #1: ffffc900000c7d20 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2711
 #2: ffffffff8e3b3150 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x14c/0xbb0 net/core/net_namespace.c:606
 #3: ffffffff8e3c0308 (rtnl_mutex){+.+.}-{3:3}, at: wg_netns_pre_exit+0x1c/0x1c0 drivers/net/wireguard/device.c:422
 #4: ffff888030ac93e8 (&wg->device_update_lock){+.+.}-{3:3}, at: wg_netns_pre_exit+0xb0/0x1c0 drivers/net/wireguard/device.c:427
 #5: ffffffff8d1379b8