INFO: task kworker/1:0:8439 blocked for more than 143 seconds.
      Not tainted 5.11.0-rc3-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:0     state:D stack:24600 pid: 8439 ppid:     2 flags:0x00004000
Workqueue: ipv6_addrconf addrconf_verify_work
Call Trace:
 context_switch kernel/sched/core.c:4313 [inline]
 __schedule+0xa4d/0xf80 kernel/sched/core.c:5064
 schedule+0x14b/0x200 kernel/sched/core.c:5143
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:5202
 __mutex_lock_common+0x11ef/0x2ef0 kernel/locking/mutex.c:1033
 __mutex_lock kernel/locking/mutex.c:1103 [inline]
 mutex_lock_nested+0x1a/0x20 kernel/locking/mutex.c:1118
 addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4569
 process_one_work+0x833/0x10c0 kernel/workqueue.c:2275
 worker_thread+0xaa4/0x1460 kernel/workqueue.c:2421
 kthread+0x39a/0x3c0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Showing all locks held in the system:
1 lock held by khungtaskd/1648:
 #0: ffffffff8c311580 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 arch/x86/pci/mmconfig_64.c:151
1 lock held by in:imklog/8149:
 #0: ffff88801887a870 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x24e/0x2f0 fs/file.c:947
3 locks held by kworker/1:0/8439:
 #0: ffff888021579538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x7aa/0x10c0 kernel/workqueue.c:2248
 #1: ffffc9000170fd20 ((addr_chk_work).work){+.+.}-{0:0}, at: process_one_work+0x7e8/0x10c0 kernel/workqueue.c:2250
 #2: ffffffff8d2ee6c8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4569
1 lock held by syz-executor594/8468:

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

NMI backtrace for cpu 1
CPU: 1 PID: 1648 Comm: khungtaskd Not tainted 5.11.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x183/0x22e lib/dump_stack.c:120
 nmi_cpu_backtrace+0x16c/0x190 lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0x191/0x2f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline]
 watchdog+0xce9/0xd30 kernel/hung_task.c:294
 kthread+0x39a/0x3c0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4882 Comm: systemd-journal Not tainted 5.11.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0033:0x7f04b09c2115
Code: 48 83 c4 48 ff 20 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 64 48 8b 14 25 08 00 00 00 48 8b 05 90 de 20 00 48 39 02 75 16 <48> 8b 07 48 c1 e0 04 48 8b 04 02 48 83 f8 ff 74 05 48 03 47 08 c3
RSP: 002b:00007fff678b0f68 EFLAGS: 00000246
RAX: 0000000000000001 RBX: 0000000000000065 RCX: 00000000000000f0
RDX: 00007f04b0bc01d0 RSI: 0000000000000000 RDI: 00007f04b09a5758
RBP: 0000000000000001 R08: 0000000000800000 R09: 0000000000000000
R10: 70f397d154649920 R11: 9b712297408b4206 R12: 000055baeedfae80
R13: 00007fff678b10b0 R14: 00007fff678b10a8 R15: 00000000002567c0
FS:  00007f04b0bbf8c0 GS:  0000000000000000