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BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:183 [inline]
BUG: KASAN: use-after-free in net_generic include/net/netns/generic.h:45 [inline]
BUG: KASAN: use-after-free in xfrm6_tunnel_pernet net/ipv6/xfrm6_tunnel.c:50 [inline]
BUG: KASAN: use-after-free in xfrm6_tunnel_free_spi net/ipv6/xfrm6_tunnel.c:199 [inline]
BUG: KASAN: use-after-free in xfrm6_tunnel_destroy+0x4c9/0x560 net/ipv6/xfrm6_tunnel.c:300
Read of size 8 at addr ffff8881cb951718 by task kworker/1:2/71

CPU: 1 PID: 71 Comm: kworker/1:2 Not tainted 4.14.95+ #14
Workqueue: events xfrm_state_gc_task
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xb9/0x10e lib/dump_stack.c:53
 print_address_description+0x60/0x226 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report mm/kasan/report.c:409 [inline]
 kasan_report.cold+0x88/0x2a5 mm/kasan/report.c:393

Allocated by task 1858:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc.part.0+0x4f/0xd0 mm/kasan/kasan.c:551
 slab_post_alloc_hook mm/slab.h:442 [inline]
 slab_alloc_node mm/slub.c:2723 [inline]
 slab_alloc mm/slub.c:2731 [inline]
 kmem_cache_alloc+0xd2/0x2d0 mm/slub.c:2736
 kmem_cache_zalloc include/linux/slab.h:651 [inline]
 net_alloc net/core/net_namespace.c:361 [inline]
 copy_net_ns+0xf7/0x440 net/core/net_namespace.c:401
 create_new_namespaces+0x366/0x750 kernel/nsproxy.c:107
 unshare_nsproxy_namespaces+0xa5/0x1e0 kernel/nsproxy.c:206
 SYSC_unshare kernel/fork.c:2386 [inline]
 SyS_unshare+0x300/0x690 kernel/fork.c:2336
 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289

Freed by task 370:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xb0/0x190 mm/kasan/kasan.c:524
 slab_free_hook mm/slub.c:1389 [inline]
 slab_free_freelist_hook mm/slub.c:1410 [inline]
 slab_free mm/slub.c:2966 [inline]
 kmem_cache_free+0xc4/0x330 mm/slub.c:2988
 net_free net/core/net_namespace.c:377 [inline]
 net_drop_ns.part.0+0x59/0x70 net/core/net_namespace.c:384
 net_drop_ns net/core/net_namespace.c:383 [inline]
 cleanup_net+0x4fd/0x860 net/core/net_namespace.c:501
 process_one_work+0x7c6/0x14e0 kernel/workqueue.c:2114
 worker_thread+0x5d7/0x1080 kernel/workqueue.c:2248
 kthread+0x310/0x420 kernel/kthread.c:232
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:402

The buggy address belongs to the object at ffff8881cb950000
 which belongs to the cache net_namespace of size 7296
The buggy address is located 5912 bytes inside of
 7296-byte region [ffff8881cb950000, ffff8881cb951c80)
The buggy address belongs to the page:
page:ffffea00072e5400 count:1 mapcount:0 mapping:          (null) index:0x0 compound_mapcount: 0
flags: 0x4000000000008100(slab|head)
raw: 4000000000008100 0000000000000000 0000000000000000 0000000100040004
raw: dead000000000100 dead000000000200 ffff8881da97f800 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881cb951600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881cb951680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881cb951700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff8881cb951780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881cb951800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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