netlink: 24 bytes leftover after parsing attributes in process `syz-executor.0'.
==================================================================
BUG: KASAN: use-after-free in net_generic include/net/netns/generic.h:46 [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:202 [inline]
BUG: KASAN: use-after-free in xfrm6_tunnel_destroy+0x4c3/0x560 net/ipv6/xfrm6_tunnel.c:303
Read of size 8 at addr ffff8880a0b32f38 by task kworker/1:0/28540

CPU: 1 PID: 28540 Comm: kworker/1:0 Not tainted 4.14.191-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events xfrm_state_gc_task
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x283 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
 kasan_report_error.cold+0x8a/0x194 mm/kasan/report.c:351
 kasan_report mm/kasan/report.c:409 [inline]
 __asan_report_load8_noabort+0x68/0x70 mm/kasan/report.c:430
 net_generic include/net/netns/generic.h:46 [inline]
 xfrm6_tunnel_pernet net/ipv6/xfrm6_tunnel.c:50 [inline]
 xfrm6_tunnel_free_spi net/ipv6/xfrm6_tunnel.c:202 [inline]
 xfrm6_tunnel_destroy+0x4c3/0x560 net/ipv6/xfrm6_tunnel.c:303
 xfrm_state_gc_destroy net/xfrm/xfrm_state.c:449 [inline]
 xfrm_state_gc_task+0x4ad/0x7e0 net/xfrm/xfrm_state.c:472
 process_one_work+0x793/0x14a0 kernel/workqueue.c:2116
 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2250
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404

Allocated by task 6383:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551
 __do_kmalloc mm/slab.c:3720 [inline]
 __kmalloc+0x15a/0x400 mm/slab.c:3729
 kmalloc include/linux/slab.h:493 [inline]
 kzalloc include/linux/slab.h:661 [inline]
 net_alloc_generic+0x1f/0x70 net/core/net_namespace.c:57
 net_alloc net/core/net_namespace.c:358 [inline]
 copy_net_ns+0xd5/0x440 net/core/net_namespace.c:402
 create_new_namespaces+0x375/0x720 kernel/nsproxy.c:107
 unshare_nsproxy_namespaces+0xa1/0x1d0 kernel/nsproxy.c:206
 SYSC_unshare kernel/fork.c:2391 [inline]
 SyS_unshare+0x308/0x7f0 kernel/fork.c:2341
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 22:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xc3/0x1a0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xc9/0x250 mm/slab.c:3815
 net_free net/core/net_namespace.c:377 [inline]
 net_drop_ns+0x54/0x70 net/core/net_namespace.c:385
 cleanup_net+0x526/0x840 net/core/net_namespace.c:502
 process_one_work+0x793/0x14a0 kernel/workqueue.c:2116
 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2250
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404

The buggy address belongs to the object at ffff8880a0b32dc0
 which belongs to the cache kmalloc-1024 of size 1024
The buggy address is located 376 bytes inside of
 1024-byte region [ffff8880a0b32dc0, ffff8880a0b331c0)
The buggy address belongs to the page:
page:ffffea000282cc80 count:1 mapcount:0 mapping:ffff8880a0b32040 index:0xffff8880a0b32940 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffff8880a0b32040 ffff8880a0b32940 0000000100000006
raw: ffffea00024619a0 ffffea0002852220 ffff88812fe52ac0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a0b32e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a0b32e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880a0b32f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                        ^
 ffff8880a0b32f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a0b33000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================