==================================================================
BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:276 [inline]
BUG: KASAN: use-after-free in dev_map_notification+0x4ef/0x5e0 kernel/bpf/devmap.c:406
Read of size 8 at addr ffff8801c5709d88 by task kworker/u4:2/27

CPU: 1 PID: 27 Comm: kworker/u4:2 Not tainted 4.13.0-rc4-next-20170811 #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
Call Trace:
 __dump_stack lib/dump_stack.c:16 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:52
 print_address_description+0x7f/0x260 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report+0x24e/0x340 mm/kasan/report.c:409
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430
 __read_once_size include/linux/compiler.h:276 [inline]
 dev_map_notification+0x4ef/0x5e0 kernel/bpf/devmap.c:406
 notifier_call_chain+0x136/0x2c0 kernel/notifier.c:93
 __raw_notifier_call_chain kernel/notifier.c:394 [inline]
 raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401
 call_netdevice_notifiers_info+0x51/0x90 net/core/dev.c:1671
 call_netdevice_notifiers net/core/dev.c:1687 [inline]
 rollback_registered_many+0x91c/0xe80 net/core/dev.c:7140
 unregister_netdevice_many.part.108+0x87/0x420 net/core/dev.c:8189
 unregister_netdevice_many+0xbb/0x100 net/core/dev.c:8188
 sit_exit_net+0x470/0x690 net/ipv6/sit.c:1857
 ops_exit_list.isra.6+0xae/0x150 net/core/net_namespace.c:142
 cleanup_net+0x5c7/0xb50 net/core/net_namespace.c:483
 process_one_work+0xbf3/0x1bc0 kernel/workqueue.c:2098
 worker_thread+0x223/0x1860 kernel/workqueue.c:2233
 kthread+0x35e/0x430 kernel/kthread.c:231
 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431

Allocated by task 9926:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xaa/0xd0 mm/kasan/kasan.c:551
 __do_kmalloc mm/slab.c:3725 [inline]
 __kmalloc+0x120/0x710 mm/slab.c:3734
 kmalloc include/linux/slab.h:498 [inline]
 bpf_map_area_alloc+0x2a/0x70 kernel/bpf/syscall.c:118
 dev_map_alloc+0x62c/0xa30 kernel/bpf/devmap.c:127
 find_and_alloc_map kernel/bpf/syscall.c:100 [inline]
 map_create kernel/bpf/syscall.c:324 [inline]
 SYSC_bpf kernel/bpf/syscall.c:1422 [inline]
 SyS_bpf+0xe1b/0x46a0 kernel/bpf/syscall.c:1403
 entry_SYSCALL_64_fastpath+0x1f/0xbe

Freed by task 3:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x6e/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xd3/0x260 mm/slab.c:3820
 kvfree+0x36/0x60 mm/util.c:416
 bpf_map_area_free+0x15/0x20 kernel/bpf/syscall.c:128
 dev_map_free+0x452/0x5a0 kernel/bpf/devmap.c:191
 bpf_map_free_deferred+0xac/0xd0 kernel/bpf/syscall.c:208
 process_one_work+0xbf3/0x1bc0 kernel/workqueue.c:2098
 worker_thread+0x223/0x1860 kernel/workqueue.c:2233
 kthread+0x35e/0x430 kernel/kthread.c:231
 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431

The buggy address belongs to the object at ffff8801c5708480
 which belongs to the cache kmalloc-8192 of size 8192
The buggy address is located 6408 bytes inside of
 8192-byte region [ffff8801c5708480, ffff8801c570a480)
The buggy address belongs to the page:
page:ffffea00063309c0 count:1 mapcount:0 mapping:ffff8801c5708480 index:0x0 compound_mapcount: 0
flags: 0x200000000008100(slab|head)
raw: 0200000000008100 ffff8801c5708480 0000000000000000 0000000100000001
raw: ffffea0006341680 ffffea000630afe0 ffff8801dbc00a00
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801c5709c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801c5709d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801c5709d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff8801c5709e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801c5709e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================