INFO: task kworker/0:1:12 blocked for more than 143 seconds.
      Not tainted 5.9.0-rc8-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:1     state:D stack:28888 pid:   12 ppid:     2 flags:0x00004000
Workqueue: ipv6_addrconf addrconf_verify_work
Call Trace:
 context_switch kernel/sched/core.c:3778 [inline]
 __schedule+0xec9/0x2280 kernel/sched/core.c:4527
 schedule+0xd0/0x2a0 kernel/sched/core.c:4602
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4661
 __mutex_lock_common kernel/locking/mutex.c:1033 [inline]
 __mutex_lock+0x3e2/0x10e0 kernel/locking/mutex.c:1103
 addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4568
 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Showing all locks held in the system:
3 locks held by kworker/0:1/12:
 #0: ffff8880996bb938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff8880996bb938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
 #0: ffff8880996bb938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
 #0: ffff8880996bb938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
 #0: ffff8880996bb938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
 #0: ffff8880996bb938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240
 #1: ffffc90000d2fda8 ((addr_chk_work).work){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244
 #2: ffffffff8b14f0c8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4568
1 lock held by khungtaskd/1172:
 #0: ffffffff8a067f40 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5852
1 lock held by in:imklog/6566:
 #0: ffff8880a8e046b0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:930
4 locks held by syz-executor527/6912:

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

NMI backtrace for cpu 0
CPU: 0 PID: 1172 Comm: khungtaskd Not tainted 5.9.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x198/0x1fd lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1b3/0x223 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+0xd7d/0x1000 kernel/hung_task.c:295
 kthread+0x3b5/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 3919 Comm: systemd-journal Not tainted 5.9.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:shmem_getpage_gfp+0x18dd/0x2430 mm/shmem.c:1989
Code: b9 c6 d5 ff 41 83 fe 03 0f 85 38 ec ff ff e9 eb f6 ff ff e8 45 ca d5 ff 48 8b ac 24 a8 00 00 00 e8 38 ca d5 ff 48 8b 74 24 08 <48> b8 00 00 00 00 00 fc ff df 48 2b 74 24 18 48 8b 54 24 68 48 c1
RSP: 0000:ffffc900052dfb08 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000800000 RCX: ffffffff81a070f3
RDX: ffff8880a6a5c340 RSI: 0000000000000235 RDI: 0000000000000006
RBP: ffffea00023f0640 R08: 0000000000000001 R09: ffffea00023f0647
R10: 0000000000235000 R11: 0000000000000000 R12: 0000000000000001
R13: 0000000000000001 R14: 0000000000235000 R15: ffff8880a6125860
FS:  00007f9ebabf08c0(0000) GS:ffff8880ae500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9eb7fa5008 CR3: 00000000a6de9000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 shmem_fault+0x1fe/0x820 mm/shmem.c:2107
 __do_fault+0x10d/0x4d0 mm/memory.c:3639
 do_shared_fault mm/memory.c:4086 [inline]
 do_fault mm/memory.c:4164 [inline]
 handle_pte_fault mm/memory.c:4400 [inline]
 __handle_mm_fault mm/memory.c:4535 [inline]
 handle_mm_fault+0x34f3/0x4590 mm/memory.c:4633
 do_user_addr_fault+0x598/0xbf0 arch/x86/mm/fault.c:1372
 handle_page_fault arch/x86/mm/fault.c:1429 [inline]
 exc_page_fault+0xa8/0x190 arch/x86/mm/fault.c:1482
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:538
RIP: 0033:0x7f9eb9efa03d
Code: 0f 82 47 e5 fc ff 0f 1f 80 00 00 00 00 48 89 f8 48 83 fa 20 72 49 48 83 fa 40 0f 87 9f 00 00 00 c5 fe 6f 06 c5 fe 6f 4c 16 e0 <c5> fe 7f 07 c5 fe 7f 4c 17 e0 c5 f8 77 c3 48 3b 15 36 54 27 00 0f
RSP: 002b:00007ffc62c0e2c8 EFLAGS: 00010283
RAX: 00007f9eb7fa5008 RBX: 000055f91fe20590 RCX: 0000000000234fc8
RDX: 0000000000000025 RSI: 000055f91fe20590 RDI: 00007f9eb7fa5008
RBP: 0000000000000025 R08: 000000000023502d R09: 000055f91fe20140
R10: 00007ffc62c0e470 R11: 11ac6e8ada2fe779 R12: 000055f91fe1fea0
R13: 0000000000000000 R14: 00007ffc62c0e478 R15: 00007f9eb7fa4fc8