syzbot

INFO: task kworker/u8:6:312 blocked for more than 143 seconds.
      Not tainted 6.14.0-rc6-syzkaller-g059f6cbcfa70 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:6    state:D stack:0     pid:312   tgid:312   ppid:2      task_flags:0x4208060 flags:0x00000008
Workqueue: ipv6_addrconf addrconf_dad_work
Call trace:
 __switch_to+0x414/0x788 arch/arm64/kernel/process.c:701 (T)
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0x1360/0x257c kernel/sched/core.c:6765
 preempt_schedule_common+0xe8/0x1dc kernel/sched/core.c:6944
 preempt_schedule+0x60/0x80 kernel/sched/core.c:6968
 __local_bh_enable_ip+0x244/0x44c kernel/softirq.c:396
 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:167 [inline]
 _raw_spin_unlock_bh+0x3c/0x4c kernel/locking/spinlock.c:210
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 netif_addr_unlock_bh include/linux/netdevice.h:4754 [inline]
 __dev_mc_add net/core/dev_addr_lists.c:873 [inline]
 dev_mc_add+0xc4/0x110 net/core/dev_addr_lists.c:886
 igmp6_group_added+0x170/0x5e4 net/ipv6/mcast.c:684
 __ipv6_dev_mc_inc+0x820/0xa80 net/ipv6/mcast.c:988
 ipv6_dev_mc_inc+0x2c/0x3c net/ipv6/mcast.c:997
 addrconf_join_solict net/ipv6/addrconf.c:2240 [inline]
 addrconf_dad_begin net/ipv6/addrconf.c:4095 [inline]
 addrconf_dad_work+0x320/0x1210 net/ipv6/addrconf.c:4223
 process_one_work+0x810/0x1638 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x97c/0xeec kernel/workqueue.c:3400
 kthread+0x65c/0x7b0 kernel/kthread.c:464
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:862

Showing all locks held in the system:
1 lock held by kthreadd/2:
3 locks held by kworker/u8:0/12:
3 locks held by kworker/u8:1/14:
1 lock held by khungtaskd/32:
 #0: ffff80008fda22e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:336
3 locks held by kworker/u8:3/45:
2 locks held by kworker/u8:4/46:
3 locks held by kworker/u8:5/173:
 #0: ffff0000c0031948 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work+0x674/0x1638 kernel/workqueue.c:3212
 #1: ffff80009bde7ba0 ((reg_check_chans).work){+.+.}-{0:0}, at: process_one_work+0x708/0x1638 kernel/workqueue.c:3212