WARNING: bad unlock balance detected! (3)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    40e196a906d9 Merge git://git.kernel.org/pub/scm/linux/kern..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12a49614c00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=7132344728e7ec3f
dashboard link: https://syzkaller.appspot.com/bug?extid=f3e3434787332dfc1c47
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
userspace arch: i386
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13a18ed4c00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+f3e3434787332dfc1c47@xxxxxxxxxxxxxxxxxxxxxxxxx

Enabling of bearer <udp:
yz1> rejected, already enabled
=====================================
Enabling of bearer <udp:
yz1> rejected, already enabled
WARNING: bad unlock balance detected!
5.0.0-rc7+ #80 Not tainted
-------------------------------------
kworker/1:1/22 is trying to release lock (
==================================================================
BUG: KASAN: slab-out-of-bounds in print_unlock_imbalance_bug  
kernel/locking/lockdep.c:3383 [inline]
BUG: KASAN: slab-out-of-bounds in  
print_unlock_imbalance_bug.cold+0x97/0x123 kernel/locking/lockdep.c:3368
Read of size 8 at addr ffff888216be498c by task kworker/1:1/22
Enabling of bearer <udp:
yz1> rejected, already enabled

CPU: 1 PID: 22 Comm: kworker/1:1 Not tainted 5.0.0-rc7+ #80
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Workqueue:  addrconf_dad_work (ipv6_addrconf)
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
 print_unlock_imbalance_bug kernel/locking/lockdep.c:3383 [inline]
 print_unlock_imbalance_bug.cold+0x97/0x123 kernel/locking/lockdep.c:3368
 __lock_release kernel/locking/lockdep.c:3601 [inline]
 lock_release+0x67e/0xa00 kernel/locking/lockdep.c:3860
 process_one_work+0xa47/0x1790 kernel/workqueue.c:2180
 worker_thread+0x98/0xe40 kernel/workqueue.c:2319
 kthread+0x357/0x430 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352

Allocated by task 1:
 save_stack+0x45/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_kmalloc mm/kasan/common.c:496 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:469
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:504
 kmem_cache_alloc_trace+0x151/0x760 mm/slab.c:3609
 kmalloc include/linux/slab.h:545 [inline]
 kzalloc include/linux/slab.h:740 [inline]
 __alloc_workqueue_key+0x79c/0xe00 kernel/workqueue.c:4099
 addrconf_init+0x9a/0x3b1 net/ipv6/addrconf.c:6906
 inet6_init+0x36c/0x6e1 net/ipv6/af_inet6.c:1022
 do_one_initcall+0x109/0x796 init/main.c:887
 do_initcall_level init/main.c:955 [inline]
 do_initcalls init/main.c:963 [inline]
 do_basic_setup init/main.c:981 [inline]
 kernel_init_freeable+0x4da/0x5c9 init/main.c:1136
 kernel_init+0x12/0x1c5 init/main.c:1054
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff888216be4780
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 12 bytes to the right of
 512-byte region [ffff888216be4780, ffff888216be4980)
The buggy address belongs to the page:
page:ffffea00085af900 count:1 mapcount:0 mapping:ffff88812c3f0940  
index:0xffff888216be4280
flags: 0x6fffc0000000200(slab)
raw: 06fffc0000000200 ffffea0008581008 ffffea0008597888 ffff88812c3f0940
raw: ffff888216be4280 ffff888216be4000 0000000100000004 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888216be4880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888216be4900: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
> ffff888216be4980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                      ^
 ffff888216be4a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888216be4a80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================


---
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