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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 ffff8880975dbfff by task syz-executor.3/12574

CPU: 0 PID: 12574 Comm: syz-executor.3 Not tainted 5.2.0-rc2+ #25
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:00007fa5f5065c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004592c9
RDX: 0000000024000000 RSI: 00000000200001c0 RDI: 0000000000000004
RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fa5f50666d4
R13: 00000000004c6f76 R14: 00000000004dc0b0 R15: 00000000ffffffff

Allocated by task 9339:
 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_kmalloc+0x9/0x10 mm/kasan/common.c:503
 __do_kmalloc mm/slab.c:3660 [inline]
 __kmalloc+0x15c/0x740 mm/slab.c:3669
 kmalloc include/linux/slab.h:552 [inline]
 tomoyo_realpath_from_path+0xcd/0x7a0 security/tomoyo/realpath.c:277
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_perm+0x230/0x430 security/tomoyo/file.c:822
 tomoyo_path_unlink+0x9b/0xe0 security/tomoyo/tomoyo.c:156
 security_path_unlink+0xfa/0x160 security/security.c:1005
 do_unlinkat+0x3b7/0x6d0 fs/namei.c:4058
 __do_sys_unlink fs/namei.c:4108 [inline]
 __se_sys_unlink fs/namei.c:4106 [inline]
 __x64_sys_unlink+0x42/0x50 fs/namei.c:4106
 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 9339:
 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]
 kfree+0xcf/0x220 mm/slab.c:3755
 tomoyo_realpath_from_path+0x1de/0x7a0 security/tomoyo/realpath.c:319
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_perm+0x230/0x430 security/tomoyo/file.c:822
 tomoyo_path_unlink+0x9b/0xe0 security/tomoyo/tomoyo.c:156
 security_path_unlink+0xfa/0x160 security/security.c:1005
 do_unlinkat+0x3b7/0x6d0 fs/namei.c:4058
 __do_sys_unlink fs/namei.c:4108 [inline]
 __se_sys_unlink fs/namei.c:4106 [inline]
 __x64_sys_unlink+0x42/0x50 fs/namei.c:4106
 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8880975dad40
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 703 bytes to the right of
 4096-byte region [ffff8880975dad40, ffff8880975dbd40)
The buggy address belongs to the page:
page:ffffea00025d7680 refcount:1 mapcount:0 mapping:ffff8880aa400dc0 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea00023cc508 ffffea00026e9a88 ffff8880aa400dc0
raw: 0000000000000000 ffff8880975dad40 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880975dbe80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880975dbf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880975dbf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                                                ^
 ffff8880975dc000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880975dc080: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
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