audit: type=1400 audit(1575221297.317:66473): avc:  denied  { net_admin } for  pid=16766 comm="syz-executor.3" capability=12  scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=cap_userns permissive=1
==================================================================
BUG: KASAN: use-after-free in xfrm6_tunnel_free_spi net/ipv6/xfrm6_tunnel.c:205 [inline]
BUG: KASAN: use-after-free in xfrm6_tunnel_destroy+0x57c/0x630 net/ipv6/xfrm6_tunnel.c:300
Read of size 8 at addr ffff8801d1c6c2b8 by task kworker/0:2/16277

CPU: 0 PID: 16277 Comm: kworker/0:2 Not tainted 4.9.141+ #23
Workqueue: events xfrm_state_gc_task
 ffff88018c24faa0 ffffffff81b42e79 ffffea0007471a00 ffff8801d1c6c2b8
 0000000000000000 ffff8801d1c6c2b8 ffff8801d4181c0c ffff88018c24fad8
 ffffffff815009b8 ffff8801d1c6c2b8 0000000000000008 0000000000000000
Call Trace:
 [<ffffffff81b42e79>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81b42e79>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff815009b8>] print_address_description+0x6c/0x234 mm/kasan/report.c:256
 [<ffffffff81500dc2>] kasan_report_error mm/kasan/report.c:355 [inline]
 [<ffffffff81500dc2>] kasan_report.cold.6+0x242/0x2fe mm/kasan/report.c:412
 [<ffffffff814f3074>] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 [<ffffffff8277785c>] xfrm6_tunnel_free_spi net/ipv6/xfrm6_tunnel.c:205 [inline]
 [<ffffffff8277785c>] xfrm6_tunnel_destroy+0x57c/0x630 net/ipv6/xfrm6_tunnel.c:300
 [<ffffffff82648c0d>] xfrm_state_gc_destroy net/xfrm/xfrm_state.c:368 [inline]
 [<ffffffff82648c0d>] xfrm_state_gc_task+0x3ad/0x510 net/xfrm/xfrm_state.c:388
 [<ffffffff81131001>] process_one_work+0x831/0x15f0 kernel/workqueue.c:2092
 [<ffffffff81131e96>] worker_thread+0xd6/0x1140 kernel/workqueue.c:2226
 [<ffffffff81142c3d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff82817a5c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373

Allocated by task 2076:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
 save_stack mm/kasan/kasan.c:505 [inline]
 set_track mm/kasan/kasan.c:517 [inline]
 kasan_kmalloc.part.1+0x62/0xf0 mm/kasan/kasan.c:609
 kasan_kmalloc+0xaf/0xc0 mm/kasan/kasan.c:594
 __kmalloc+0x12f/0x310 mm/slub.c:3741
 kmalloc include/linux/slab.h:495 [inline]
 kzalloc include/linux/slab.h:636 [inline]
 ops_init+0xef/0x3a0 net/core/net_namespace.c:101
 setup_net+0x1bc/0x4d0 net/core/net_namespace.c:291
 copy_net_ns+0x189/0x330 net/core/net_namespace.c:408
 create_new_namespaces+0x501/0x760 kernel/nsproxy.c:106
 unshare_nsproxy_namespaces+0xa5/0x1d0 kernel/nsproxy.c:205
 SYSC_unshare kernel/fork.c:2263 [inline]
 SyS_unshare+0x319/0x710 kernel/fork.c:2213
 do_syscall_32_irqs_on arch/x86/entry/common.c:328 [inline]
 do_fast_syscall_32+0x2f1/0xa10 arch/x86/entry/common.c:390
 entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137

Freed by task 10612:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
 save_stack mm/kasan/kasan.c:505 [inline]
 set_track mm/kasan/kasan.c:517 [inline]
 kasan_slab_free+0xac/0x190 mm/kasan/kasan.c:582
 slab_free_hook mm/slub.c:1355 [inline]
 slab_free_freelist_hook mm/slub.c:1377 [inline]
 slab_free mm/slub.c:2958 [inline]
 kfree+0xfb/0x310 mm/slub.c:3878
 ops_free net/core/net_namespace.c:126 [inline]
 ops_free_list.part.3+0x1ff/0x330 net/core/net_namespace.c:148
 ops_free_list net/core/net_namespace.c:146 [inline]
 cleanup_net+0x490/0x8b0 net/core/net_namespace.c:477
 process_one_work+0x831/0x15f0 kernel/workqueue.c:2092
 worker_thread+0xd6/0x1140 kernel/workqueue.c:2226
 kthread+0x26d/0x300 kernel/kthread.c:211
 ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373

The buggy address belongs to the object at ffff8801d1c6c200
 which belongs to the cache kmalloc-8192 of size 8192
The buggy address is located 184 bytes inside of
 8192-byte region [ffff8801d1c6c200, ffff8801d1c6e200)
The buggy address belongs to the page:
page:ffffea0007471a00 count:1 mapcount:0 mapping:          (null) index:0x0 compound_mapcount: 0
flags: 0x4000000000004080(slab|head)
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d1c6c180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801d1c6c200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801d1c6c280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                        ^
 ffff8801d1c6c300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801d1c6c380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================