==================================================================
BUG: KASAN: slab-out-of-bounds in ip6_tnl_xmit2+0x1f95/0x2320 net/ipv6/ip6_tunnel.c:987
Read of size 16 at addr ffff8800a23c9930 by task syz-executor.3/15218

CPU: 0 PID: 15218 Comm: syz-executor.3 Not tainted 4.4.174+ #4
 0000000000000000 c5eb287002980e31 ffff8801ba5972a0 ffffffff81aad1a1
 0000000000000000 ffffea000288f200 ffff8800a23c9930 0000000000000010
 ffff8800a23c9680 ffff8801ba5972d8 ffffffff81490120 0000000000000000
Call Trace:
 [<ffffffff81aad1a1>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81aad1a1>] dump_stack+0xc1/0x120 lib/dump_stack.c:51
 [<ffffffff81490120>] print_address_description+0x6f/0x21b mm/kasan/report.c:252
 [<ffffffff81490358>] kasan_report_error mm/kasan/report.c:351 [inline]
 [<ffffffff81490358>] kasan_report mm/kasan/report.c:408 [inline]
 [<ffffffff81490358>] kasan_report.cold+0x8c/0x2be mm/kasan/report.c:393
 [<ffffffff81484faf>] __asan_report_load_n_noabort+0xf/0x20 mm/kasan/report.c:439
 [<ffffffff826b3105>] ip6_tnl_xmit2+0x1f95/0x2320 net/ipv6/ip6_tunnel.c:987
 [<ffffffff826b4e59>] ip4ip6_tnl_xmit net/ipv6/ip6_tunnel.c:1134 [inline]
 [<ffffffff826b4e59>] ip6_tnl_xmit+0xa09/0xe00 net/ipv6/ip6_tunnel.c:1212
 [<ffffffff82245071>] __netdev_start_xmit include/linux/netdevice.h:3750 [inline]
 [<ffffffff82245071>] netdev_start_xmit include/linux/netdevice.h:3759 [inline]
 [<ffffffff82245071>] xmit_one net/core/dev.c:2781 [inline]
 [<ffffffff82245071>] dev_hard_start_xmit+0x7c1/0x11e0 net/core/dev.c:2797
 [<ffffffff822473cb>] __dev_queue_xmit+0x164b/0x1bb0 net/core/dev.c:3229
 [<ffffffff82247948>] dev_queue_xmit+0x18/0x20 net/core/dev.c:3263
 [<ffffffff8225c136>] neigh_direct_output+0x16/0x20 net/core/neighbour.c:1369
 [<ffffffff823c5412>] dst_neigh_output include/net/dst.h:461 [inline]
 [<ffffffff823c5412>] ip_finish_output2+0x6a2/0x1280 net/ipv4/ip_output.c:213
 [<ffffffff823cc6e2>] ip_finish_output+0x8b2/0xc60 net/ipv4/ip_output.c:288
 [<ffffffff823d04a7>] NF_HOOK_COND include/linux/netfilter.h:240 [inline]
 [<ffffffff823d04a7>] ip_output+0x227/0x4c0 net/ipv4/ip_output.c:362
 [<ffffffff823cd21c>] dst_output include/net/dst.h:498 [inline]
 [<ffffffff823cd21c>] ip_local_out+0x9c/0x180 net/ipv4/ip_output.c:119
 [<ffffffff823ce58c>] ip_queue_xmit+0x89c/0x1ab0 net/ipv4/ip_output.c:461
 [<ffffffff82431dd4>] __tcp_transmit_skb+0x1904/0x2cf0 net/ipv4/tcp_output.c:1034
 [<ffffffff824337e4>] tcp_transmit_skb net/ipv4/tcp_output.c:1047 [inline]
 [<ffffffff824337e4>] tcp_write_xmit+0x624/0x4570 net/ipv4/tcp_output.c:2137
 [<ffffffff82437fcb>] __tcp_push_pending_frames+0xab/0x2b0 net/ipv4/tcp_output.c:2323
 [<ffffffff8243eeab>] tcp_send_fin+0x15b/0xa90 net/ipv4/tcp_output.c:2899
 [<ffffffff823f5b02>] tcp_shutdown net/ipv4/tcp.c:2008 [inline]
 [<ffffffff823f5b02>] tcp_shutdown+0xe2/0x110 net/ipv4/tcp.c:1993
 [<ffffffff824a675b>] inet_shutdown+0x17b/0x360 net/ipv4/af_inet.c:825
 [<ffffffff821dcf5b>] SYSC_shutdown net/socket.c:1832 [inline]
 [<ffffffff821dcf5b>] SyS_shutdown+0xfb/0x1a0 net/socket.c:1823
 [<ffffffff82718ba1>] entry_SYSCALL_64_fastpath+0x1e/0x9a

Allocated by task 15218:
 [<ffffffff8102e3c6>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff81483f22>] save_stack mm/kasan/kasan.c:512 [inline]
 [<ffffffff81483f22>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff81483f22>] kasan_kmalloc.part.0+0x62/0xf0 mm/kasan/kasan.c:616
 [<ffffffff81484197>] kasan_kmalloc+0xb7/0xd0 mm/kasan/kasan.c:601
 [<ffffffff81480521>] __kmalloc+0x141/0x330 mm/slub.c:3613
 [<ffffffff82264216>] kmalloc include/linux/slab.h:481 [inline]
 [<ffffffff82264216>] kzalloc include/linux/slab.h:620 [inline]
 [<ffffffff82264216>] neigh_alloc net/core/neighbour.c:285 [inline]
 [<ffffffff82264216>] __neigh_create+0x1d6/0x1b30 net/core/neighbour.c:457
 [<ffffffff823a024e>] neigh_create include/net/neighbour.h:313 [inline]
 [<ffffffff823a024e>] ipv4_neigh_lookup+0x52e/0x6e0 net/ipv4/route.c:464
 [<ffffffff826b13eb>] dst_neigh_lookup include/net/dst.h:466 [inline]
 [<ffffffff826b13eb>] ip6_tnl_xmit2+0x27b/0x2320 net/ipv6/ip6_tunnel.c:982
 [<ffffffff826b4e59>] ip4ip6_tnl_xmit net/ipv6/ip6_tunnel.c:1134 [inline]
 [<ffffffff826b4e59>] ip6_tnl_xmit+0xa09/0xe00 net/ipv6/ip6_tunnel.c:1212
 [<ffffffff82245071>] __netdev_start_xmit include/linux/netdevice.h:3750 [inline]
 [<ffffffff82245071>] netdev_start_xmit include/linux/netdevice.h:3759 [inline]
 [<ffffffff82245071>] xmit_one net/core/dev.c:2781 [inline]
 [<ffffffff82245071>] dev_hard_start_xmit+0x7c1/0x11e0 net/core/dev.c:2797
 [<ffffffff822473cb>] __dev_queue_xmit+0x164b/0x1bb0 net/core/dev.c:3229
 [<ffffffff82247948>] dev_queue_xmit+0x18/0x20 net/core/dev.c:3263
 [<ffffffff8225c136>] neigh_direct_output+0x16/0x20 net/core/neighbour.c:1369
 [<ffffffff823c5412>] dst_neigh_output include/net/dst.h:461 [inline]
 [<ffffffff823c5412>] ip_finish_output2+0x6a2/0x1280 net/ipv4/ip_output.c:213
 [<ffffffff823cc6e2>] ip_finish_output+0x8b2/0xc60 net/ipv4/ip_output.c:288
 [<ffffffff823d04a7>] NF_HOOK_COND include/linux/netfilter.h:240 [inline]
 [<ffffffff823d04a7>] ip_output+0x227/0x4c0 net/ipv4/ip_output.c:362
 [<ffffffff823cd21c>] dst_output include/net/dst.h:498 [inline]
 [<ffffffff823cd21c>] ip_local_out+0x9c/0x180 net/ipv4/ip_output.c:119
 [<ffffffff823ce58c>] ip_queue_xmit+0x89c/0x1ab0 net/ipv4/ip_output.c:461
 [<ffffffff82431dd4>] __tcp_transmit_skb+0x1904/0x2cf0 net/ipv4/tcp_output.c:1034
 [<ffffffff824337e4>] tcp_transmit_skb net/ipv4/tcp_output.c:1047 [inline]
 [<ffffffff824337e4>] tcp_write_xmit+0x624/0x4570 net/ipv4/tcp_output.c:2137
 [<ffffffff82437fcb>] __tcp_push_pending_frames+0xab/0x2b0 net/ipv4/tcp_output.c:2323
 [<ffffffff8243eeab>] tcp_send_fin+0x15b/0xa90 net/ipv4/tcp_output.c:2899
 [<ffffffff823f5b02>] tcp_shutdown net/ipv4/tcp.c:2008 [inline]
 [<ffffffff823f5b02>] tcp_shutdown+0xe2/0x110 net/ipv4/tcp.c:1993
 [<ffffffff824a675b>] inet_shutdown+0x17b/0x360 net/ipv4/af_inet.c:825
 [<ffffffff821dcf5b>] SYSC_shutdown net/socket.c:1832 [inline]
 [<ffffffff821dcf5b>] SyS_shutdown+0xfb/0x1a0 net/socket.c:1823
 [<ffffffff82718ba1>] entry_SYSCALL_64_fastpath+0x1e/0x9a

Freed by task 14279:
 [<ffffffff8102e3c6>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff81484820>] save_stack mm/kasan/kasan.c:512 [inline]
 [<ffffffff81484820>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff81484820>] kasan_slab_free+0xb0/0x190 mm/kasan/kasan.c:589
 [<ffffffff81481c44>] slab_free_hook mm/slub.c:1383 [inline]
 [<ffffffff81481c44>] slab_free_freelist_hook mm/slub.c:1405 [inline]
 [<ffffffff81481c44>] slab_free mm/slub.c:2859 [inline]
 [<ffffffff81481c44>] kfree+0xf4/0x310 mm/slub.c:3749
 [<ffffffff821fd036>] skb_free_head net/core/skbuff.c:571 [inline]
 [<ffffffff821fd036>] skb_release_data+0x2e6/0x380 net/core/skbuff.c:602
 [<ffffffff821fd11d>] skb_release_all+0x4d/0x60 net/core/skbuff.c:661
 [<ffffffff821fd146>] __kfree_skb+0x16/0x30 net/core/skbuff.c:675
 [<ffffffff82415fb3>] tcp_data_queue+0x1d43/0x3a90 net/ipv4/tcp_input.c:4605
 [<ffffffff82422a99>] tcp_rcv_established+0x599/0x2070 net/ipv4/tcp_input.c:5538
 [<ffffffff8264b3f4>] tcp_v6_do_rcv+0xdb4/0x11d0 net/ipv6/tcp_ipv6.c:1267
 [<ffffffff8264dcfe>] tcp_v6_rcv+0x24ee/0x30b0 net/ipv6/tcp_ipv6.c:1477
 [<ffffffff825b3c1d>] ip6_input_finish+0x57d/0x14f0 net/ipv6/ip6_input.c:248
 [<ffffffff825b66a8>] NF_HOOK_THRESH include/linux/netfilter.h:226 [inline]
 [<ffffffff825b66a8>] NF_HOOK include/linux/netfilter.h:249 [inline]
 [<ffffffff825b66a8>] ip6_input+0xf8/0x1f0 net/ipv6/ip6_input.c:280
 [<ffffffff825b317d>] dst_input include/net/dst.h:504 [inline]
 [<ffffffff825b317d>] ip6_rcv_finish+0x14d/0x670 net/ipv6/ip6_input.c:62
 [<ffffffff825b5b51>] NF_HOOK_THRESH include/linux/netfilter.h:226 [inline]
 [<ffffffff825b5b51>] NF_HOOK include/linux/netfilter.h:249 [inline]
 [<ffffffff825b5b51>] ipv6_rcv+0xfc1/0x1a20 net/ipv6/ip6_input.c:186
 [<ffffffff82230640>] __netif_receive_skb_core+0x1300/0x2950 net/core/dev.c:4041
 [<ffffffff82238bd8>] __netif_receive_skb+0x58/0x1c0 net/core/dev.c:4076
 [<ffffffff8223fec0>] process_backlog+0x200/0x630 net/core/dev.c:4673
 [<ffffffff8223f2f7>] napi_poll net/core/dev.c:4911 [inline]
 [<ffffffff8223f2f7>] net_rx_action+0x367/0xd30 net/core/dev.c:4976
 [<ffffffff8271bb16>] __do_softirq+0x226/0xa3f kernel/softirq.c:273

The buggy address belongs to the object at ffff8800a23c9680
 which belongs to the cache kmalloc-1024 of size 1024
The buggy address is located 688 bytes inside of
 1024-byte region [ffff8800a23c9680, ffff8800a23c9a80)
The buggy address belongs to the page:
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access[  544.892103] ------------[ cut here ]------------
WARNING: CPU: 1 PID: 2117 at kernel/sched/core.c:7941 __might_sleep+0x138/0x1a0 kernel/sched/core.c:7941()
do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff810de6f5>] do_wait+0x265/0xa00 kernel/exit.c:1511