==================================================================
BUG: KASAN: slab-out-of-bounds in ip6_tnl_xmit2+0x1f95/0x2320 net/ipv6/ip6_tunnel.c:987
Read of size 16 at addr ffff8801d44742b0 by task syz-executor.4/8739

CPU: 0 PID: 8739 Comm: syz-executor.4 Not tainted 4.4.174+ #17
 0000000000000000 d3b3964863183fcd ffff8801b5af6b30 ffffffff81aad1a1
 0000000000000000 ffffea0007511d00 ffff8801d44742b0 0000000000000010
 ffff8801d4474000 ffff8801b5af6b68 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
 [<ffffffff823c805c>] ip_do_fragment+0x187c/0x1f70 net/ipv4/ip_output.c:635
 [<ffffffff823cbd7b>] ip_fragment.constprop.0+0x14b/0x200 net/ipv4/ip_output.c:505
 [<ffffffff823cc1e9>] ip_finish_output+0x3b9/0xc60 net/ipv4/ip_output.c:286
 [<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
 [<ffffffff823d300e>] ip_send_skb+0x3e/0xc0 net/ipv4/ip_output.c:1453
 [<ffffffff82478ded>] udp_send_skb+0x4fd/0xc70 net/ipv4/udp.c:842
 [<ffffffff824795ae>] udp_push_pending_frames+0x4e/0xe0 net/ipv4/udp.c:870
 [<ffffffff8247f63b>] udp_sendmsg+0x116b/0x1c60 net/ipv4/udp.c:1104
 [<ffffffff8261430d>] udpv6_sendmsg+0x1e5d/0x24f0 net/ipv6/udp.c:1178
 [<ffffffff824a8b42>] inet_sendmsg+0x202/0x4d0 net/ipv4/af_inet.c:755
 [<ffffffff821d838e>] sock_sendmsg_nosec net/socket.c:638 [inline]
 [<ffffffff821d838e>] sock_sendmsg+0xbe/0x110 net/socket.c:648
 [<ffffffff821d9e69>] ___sys_sendmsg+0x369/0x890 net/socket.c:1975
 [<ffffffff821dd386>] __sys_sendmmsg+0x1d6/0x2e0 net/socket.c:2053
 [<ffffffff822ace22>] C_SYSC_sendmmsg net/compat.c:731 [inline]
 [<ffffffff822ace22>] compat_SyS_sendmmsg+0x32/0x40 net/compat.c:728
 [<ffffffff8100603d>] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline]
 [<ffffffff8100603d>] do_fast_syscall_32+0x32d/0xa90 arch/x86/entry/common.c:397
 [<ffffffff8271a350>] sysenter_flags_fixed+0xd/0x1a

Allocated by task 8739:
 [<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
 [<ffffffff823c805c>] ip_do_fragment+0x187c/0x1f70 net/ipv4/ip_output.c:635
 [<ffffffff823cbd7b>] ip_fragment.constprop.0+0x14b/0x200 net/ipv4/ip_output.c:505
 [<ffffffff823cc1e9>] ip_finish_output+0x3b9/0xc60 net/ipv4/ip_output.c:286
 [<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
 [<ffffffff823d300e>] ip_send_skb+0x3e/0xc0 net/ipv4/ip_output.c:1453
 [<ffffffff82478ded>] udp_send_skb+0x4fd/0xc70 net/ipv4/udp.c:842
 [<ffffffff824795ae>] udp_push_pending_frames+0x4e/0xe0 net/ipv4/udp.c:870
 [<ffffffff8247f63b>] udp_sendmsg+0x116b/0x1c60 net/ipv4/udp.c:1104
 [<ffffffff8261430d>] udpv6_sendmsg+0x1e5d/0x24f0 net/ipv6/udp.c:1178
 [<ffffffff824a8b42>] inet_sendmsg+0x202/0x4d0 net/ipv4/af_inet.c:755
 [<ffffffff821d838e>] sock_sendmsg_nosec net/socket.c:638 [inline]
 [<ffffffff821d838e>] sock_sendmsg+0xbe/0x110 net/socket.c:648
 [<ffffffff821d9e69>] ___sys_sendmsg+0x369/0x890 net/socket.c:1975
 [<ffffffff821dd386>] __sys_sendmmsg+0x1d6/0x2e0 net/socket.c:2053
 [<ffffffff822ace22>] C_SYSC_sendmmsg net/compat.c:731 [inline]
 [<ffffffff822ace22>] compat_SyS_sendmmsg+0x32/0x40 net/compat.c:728
 [<ffffffff8100603d>] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline]
 [<ffffffff8100603d>] do_fast_syscall_32+0x32d/0xa90 arch/x86/entry/common.c:397
 [<ffffffff8271a350>] sysenter_flags_fixed+0xd/0x1a

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff8801d4474000
 which belongs to the cache kmalloc-1024 of size 1024
The buggy address is located 688 bytes inside of
 1024-byte region [ffff8801d4474000, ffff8801d4474400)
The buggy address belongs to the page:
BUG: unable to handle kernel NULL pointer dereference at 000000000000006a
IP: [<ffffffff82891beb>] str__compaction__trace_system_name+0x46b/0xec0
PGD 1d09d2067 PUD 1d3d83067 PMD 0 
Oops: 0002 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 8723 Comm: syz-executor.4 Not tainted 4.4.174+ #17
task: ffff8800b1be4740 task.stack: ffff8800965a0000
RIP: 0010:[<ffffffff82891beb>]  [<ffffffff82891beb>] str__compaction__trace_system_name+0x46b/0xec0
RSP: 0018:ffff8801db707520  EFLAGS: 00010206
RAX: ffffffff82891be0 RBX: ffff8801d4474400 RCX: ffffffff831a78f0
RDX: 0000000000000100 RSI: ffff88009e0d0000 RDI: ffffffff82244a23
RBP: ffff8801db7075d8 R08: 0000000000000009 R09: ffff8800b1be5190
R10: ffffffff82836880 R11: 0000000000000000 R12: ffff88009e0d0000
R13: 0000000000000000 R14: ffff8801ae15cc80 R15: ffff8801db7075d8
FS:  0000000000000000(0000) GS:ffff8801db700000(0063) knlGS:00000000f55c1b40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 000000000000006a CR3: 00000001cf635000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff82891be0 ffffffff82244963 ffff8801db707680 ffffed0016822232
 ffff8800ba6160f8 ffff8800b41112f0 ffff8800b4111190 ffffed00174c2c1f
 00ff880000000000 0000000000000000 0000000000000000 ffffffff82891be0
Call Trace:
 <IRQ> 
 [<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
 [<ffffffff8243c54a>] tcp_transmit_skb net/ipv4/tcp_output.c:1047 [inline]
 [<ffffffff8243c54a>] __tcp_retransmit_skb+0x5ea/0x1710 net/ipv4/tcp_output.c:2665
 [<ffffffff8243de33>] tcp_retransmit_skb+0x23/0x2c0 net/ipv4/tcp_output.c:2682
 [<ffffffff8244394e>] tcp_retransmit_timer net/ipv4/tcp_timer.c:461 [inline]
 [<ffffffff8244394e>] tcp_retransmit_timer+0x7ee/0x1f70 net/ipv4/tcp_timer.c:379
 [<ffffffff8244548c>] tcp_write_timer_handler+0x3bc/0x700 net/ipv4/tcp_timer.c:543
 [<ffffffff8244588d>] tcp_write_timer+0xbd/0xd0 net/ipv4/tcp_timer.c:561
 [<ffffffff812582dd>] call_timer_fn+0x18d/0x850 kernel/time/timer.c:1185
 [<ffffffff81258ebf>] __run_timers kernel/time/timer.c:1261 [inline]
 [<ffffffff81258ebf>] run_timer_softirq+0x51f/0xb70 kernel/time/timer.c:1444
 [<ffffffff8271bb16>] __do_softirq+0x226/0xa3f kernel/softirq.c:273
 [<ffffffff810e1a8a>] invoke_softirq kernel/softirq.c:350 [inline]
 [<ffffffff810e1a8a>] irq_exit+0x10a/0x150 kernel/softirq.c:391
 [<ffffffff8271b24e>] exiting_irq arch/x86/include/asm/apic.h:652 [inline]
 [<ffffffff8271b24e>] smp_apic_timer_interrupt+0x7e/0xb0 arch/x86/kernel/apic/apic.c:926
 [<ffffffff8271a59d>] apic_timer_interrupt+0x9d/0xb0 arch/x86/entry/entry_64.S:768
 <EOI> 
 [<ffffffff81299a20>] smp_call_function_many+0x5c0/0x730 kernel/smp.c:435
 [<ffffffff810bbc70>] native_flush_tlb_others+0x110/0x710 arch/x86/mm/tlb.c:325
 [<ffffffff810bc37e>] flush_tlb_others arch/x86/include/asm/paravirt.h:338 [inline]
 [<ffffffff810bc37e>] flush_tlb_mm_range+0x10e/0x550 arch/x86/mm/tlb.c:391
 [<ffffffff81461f77>] flush_tlb_page arch/x86/include/asm/tlbflush.h:300 [inline]
 [<ffffffff81461f77>] ptep_clear_flush+0xe7/0x120 mm/pgtable-generic.c:80
 [<ffffffff81430223>] wp_page_copy.isra.0+0x6e3/0xc70 mm/memory.c:2202
 [<ffffffff81433bda>] do_wp_page+0x23a/0x1340 mm/memory.c:2441
 [<ffffffff8143b2e4>] handle_pte_fault mm/memory.c:3362 [inline]
 [<ffffffff8143b2e4>] __handle_mm_fault mm/memory.c:3474 [inline]
 [<ffffffff8143b2e4>] handle_mm_fault+0x1614/0x3140 mm/memory.c:3503
 [<ffffffff810aaa4e>] __do_page_fault+0x28e/0x7f0 arch/x86/mm/fault.c:1243
 [<ffffffff810ab008>] do_page_fault+0x28/0x30 arch/x86/mm/fault.c:1306
 [<ffffffff82719e35>] page_fault+0x25/0x30 arch/x86/entry/entry_64.S:1064
 [<ffffffff814b17a4>] pipe_read+0x274/0x860 fs/pipe.c:270
 [<ffffffff81496725>] new_sync_read fs/read_write.c:424 [inline]
 [<ffffffff81496725>] __vfs_read+0x2e5/0x3c0 fs/read_write.c:436
 [<ffffffff81498264>] vfs_read+0x134/0x360 fs/read_write.c:456
 [<ffffffff8149aa8c>] SYSC_read fs/read_write.c:571 [inline]
 [<ffffffff8149aa8c>] SyS_read+0xdc/0x1c0 fs/read_write.c:564
 [<ffffffff8100603d>] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline]
 [<ffffffff8100603d>] do_fast_syscall_32+0x32d/0xa90 arch/x86/entry/common.c:397
 [<ffffffff8271a350>] sysenter_flags_fixed+0xd/0x1a
Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 56 4d 5f 42 55 47 5f 4f 4e 5f 50 <41> 47 45 28 50 61 67 65 53 6c 61 62 28 70 61 67 65 29 29 00 00 
RIP  [<ffffffff82891beb>] str__compaction__trace_system_name+0x46b/0xec0
 RSP <ffff8801db707520>
CR2: 000000000000006a
---[ end trace cb292b000bf394ae ]---