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BUG: KASAN: slab-out-of-bounds in ip6_dst_lookup_tail+0x196a/0x1b30 net/ipv6/ip6_output.c:1071
Read of size 8 at addr ffff8880858b0a3f by task syz-executor.3/18924

CPU: 0 PID: 18924 Comm: syz-executor.3 Not tainted 5.2.0-rc2+ #22
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:188
 __kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 kasan_report+0x12/0x20 mm/kasan/common.c:614
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132
 ip6_dst_lookup_tail+0x196a/0x1b30 net/ipv6/ip6_output.c:1071
 ip6_dst_lookup+0x4d/0x70 net/ipv6/ip6_output.c:1134
 icmpv6_route_lookup+0x346/0x4d0 net/ipv6/icmp.c:377
 icmp6_send+0x12b8/0x1e50 net/ipv6/icmp.c:556
 icmpv6_send+0xec/0x230 net/ipv6/ip6_icmp.c:43
 __udp6_lib_rcv+0x1ad1/0x2cc0 net/ipv6/udp.c:938
 udplitev6_rcv+0x22/0x30 net/ipv6/udplite.c:20
 ip6_protocol_deliver_rcu+0x2fe/0x16c0 net/ipv6/ip6_input.c:401
 ip6_input_finish+0x84/0x170 net/ipv6/ip6_input.c:442
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ip6_input+0xe4/0x3f0 net/ipv6/ip6_input.c:451
 dst_input include/net/dst.h:439 [inline]
 ip6_rcv_finish+0x1de/0x310 net/ipv6/ip6_input.c:80
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ipv6_rcv+0x10e/0x420 net/ipv6/ip6_input.c:276
 __netif_receive_skb_one_core+0x113/0x1a0 net/core/dev.c:4985
 __netif_receive_skb+0x2c/0x1d0 net/core/dev.c:5099
 process_backlog+0x206/0x750 net/core/dev.c:5910
 napi_poll net/core/dev.c:6333 [inline]
 net_rx_action+0x4f5/0x1070 net/core/dev.c:6399
 __do_softirq+0x25c/0x94c kernel/softirq.c:293
 do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1040
 </IRQ>
 do_softirq.part.0+0x11a/0x170 kernel/softirq.c:338
 do_softirq kernel/softirq.c:330 [inline]
 __local_bh_enable_ip+0x211/0x270 kernel/softirq.c:190
 local_bh_enable include/linux/bottom_half.h:32 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:684 [inline]
 ip6_finish_output2+0x10a0/0x2550 net/ipv6/ip6_output.c:121
 __ip6_finish_output+0x444/0xaa0 net/ipv6/ip6_output.c:146
 ip6_finish_output+0x38/0x1f0 net/ipv6/ip6_output.c:156
 NF_HOOK_COND include/linux/netfilter.h:294 [inline]
 ip6_output+0x235/0x7f0 net/ipv6/ip6_output.c:179
 dst_output include/net/dst.h:433 [inline]
 ip6_local_out+0xbb/0x1b0 net/ipv6/output_core.c:179
 ip6_send_skb+0xbb/0x350 net/ipv6/ip6_output.c:1796
 udp_v6_send_skb.isra.0+0x839/0x14f0 net/ipv6/udp.c:1180
 udpv6_sendmsg+0x21e0/0x28d0 net/ipv6/udp.c:1477
 inet_sendmsg+0x141/0x5d0 net/ipv4/af_inet.c:802
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:671
 ___sys_sendmsg+0x803/0x920 net/socket.c:2292
 __sys_sendmsg+0x105/0x1d0 net/socket.c:2330
 __do_sys_sendmsg net/socket.c:2339 [inline]
 __se_sys_sendmsg net/socket.c:2337 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2337
 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4592c9
Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f6019847c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004592c9
RDX: 0000000000000000 RSI: 0000000020000740 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f60198486d4
R13: 00000000004c6f76 R14: 00000000004dc0b0 R15: 00000000ffffffff

Allocated by task 10342:
 save_stack+0x23/0x90 mm/kasan/common.c:71
 set_track mm/kasan/common.c:79 [inline]
 __kasan_kmalloc mm/kasan/common.c:489 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:462
 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:497
 slab_post_alloc_hook mm/slab.h:437 [inline]
 slab_alloc mm/slab.c:3326 [inline]
 kmem_cache_alloc+0x11a/0x6f0 mm/slab.c:3488
 dst_alloc+0x10e/0x200 net/core/dst.c:93
 ip6_dst_alloc+0x34/0xa0 net/ipv6/route.c:356
 ip6_rt_pcpu_alloc net/ipv6/route.c:1257 [inline]
 rt6_make_pcpu_route net/ipv6/route.c:1287 [inline]
 ip6_pol_route+0x649/0x1010 net/ipv6/route.c:2031
 ip6_pol_route_output+0x54/0x70 net/ipv6/route.c:2204
 fib6_rule_lookup+0x133/0x5a0 net/ipv6/fib6_rules.c:116
 ip6_route_output_flags+0x2c4/0x350 net/ipv6/route.c:2233
 ip6_route_output include/net/ip6_route.h:89 [inline]
 icmpv6_xrlim_allow+0x11e/0x440 net/ipv6/icmp.c:212
 icmp6_send+0x1107/0x1e50 net/ipv6/icmp.c:540
 icmpv6_send+0xec/0x230 net/ipv6/ip6_icmp.c:43
 ip6_pkt_drop+0x330/0x760 net/ipv6/route.c:3925
 ip6_pkt_discard_out+0xaa/0x190 net/ipv6/route.c:3938
 dst_output include/net/dst.h:433 [inline]
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ip6_xmit+0xe35/0x20b0 net/ipv6/ip6_output.c:283
 sctp_v6_xmit+0x313/0x660 net/sctp/ipv6.c:217
 sctp_packet_transmit+0x1ba5/0x36c0 net/sctp/output.c:626
 sctp_packet_singleton net/sctp/outqueue.c:772 [inline]
 sctp_outq_flush_ctrl.constprop.0+0x73c/0xd30 net/sctp/outqueue.c:903
 sctp_outq_flush+0xe8/0x2780 net/sctp/outqueue.c:1185
 sctp_outq_uncork+0x6c/0x80 net/sctp/outqueue.c:757
 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1776 [inline]
 sctp_side_effects net/sctp/sm_sideeffect.c:1179 [inline]
 sctp_do_sm+0x504/0x50e0 net/sctp/sm_sideeffect.c:1150
 sctp_primitive_ASSOCIATE+0x9d/0xd0 net/sctp/primitive.c:73
 sctp_sendmsg_to_asoc+0xc50/0x1f10 net/sctp/socket.c:1912
 sctp_sendmsg+0x109a/0x17d0 net/sctp/socket.c:2102
 inet_sendmsg+0x141/0x5d0 net/ipv4/af_inet.c:802
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:671
 ___sys_sendmsg+0x803/0x920 net/socket.c:2292
 __sys_sendmsg+0x105/0x1d0 net/socket.c:2330
 __do_sys_sendmsg net/socket.c:2339 [inline]
 __se_sys_sendmsg net/socket.c:2337 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2337
 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 9268:
 save_stack+0x23/0x90 mm/kasan/common.c:71
 set_track mm/kasan/common.c:79 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:451
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:459
 __cache_free mm/slab.c:3432 [inline]
 kmem_cache_free+0x86/0x260 mm/slab.c:3698
 dst_destroy+0x29e/0x3c0 net/core/dst.c:129
 dst_destroy_rcu+0x16/0x19 net/core/dst.c:142
 __rcu_reclaim kernel/rcu/rcu.h:222 [inline]
 rcu_do_batch kernel/rcu/tree.c:2092 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2310 [inline]
 rcu_core+0xba5/0x1500 kernel/rcu/tree.c:2291
 __do_softirq+0x25c/0x94c kernel/softirq.c:293

The buggy address belongs to the object at ffff8880858b0900
 which belongs to the cache ip6_dst_cache of size 224
The buggy address is located 95 bytes to the right of
 224-byte region [ffff8880858b0900, ffff8880858b09e0)
The buggy address belongs to the page:
page:ffffea0002162c00 refcount:1 mapcount:0 mapping:ffff88809b76f6c0 index:0xffff8880858b0400
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea00029e4ac8 ffffea000259a608 ffff88809b76f6c0
raw: ffff8880858b0400 ffff8880858b0040 0000000100000007 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880858b0900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880858b0980: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
>ffff8880858b0a00: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
                                        ^
 ffff8880858b0a80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880858b0b00: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc
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