==================================================================
BUG: KASAN: slab-out-of-bounds in u32_match_it net/netfilter/xt_u32.c:79 [inline]
BUG: KASAN: slab-out-of-bounds in u32_mt+0x55c/0x5c0 net/netfilter/xt_u32.c:94
Read of size 4 at addr ffff88809417b940 by task syz-executor615/7562

CPU: 0 PID: 7562 Comm: syz-executor615 Not tainted 4.14.169-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x142/0x197 lib/dump_stack.c:58
 print_address_description.cold+0x7c/0x1dc mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report mm/kasan/report.c:409 [inline]
 kasan_report.cold+0xa9/0x2af mm/kasan/report.c:393
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:429
 u32_match_it net/netfilter/xt_u32.c:79 [inline]
 u32_mt+0x55c/0x5c0 net/netfilter/xt_u32.c:94
 ip6t_do_table+0x813/0x1860 net/ipv6/netfilter/ip6_tables.c:324
 ip6table_filter_hook+0x65/0x80 net/ipv6/netfilter/ip6table_filter.c:41
 nf_hook_entry_hookfn include/linux/netfilter.h:108 [inline]
 nf_hook_slow+0xaf/0x1b0 net/netfilter/core.c:467
 nf_hook include/linux/netfilter.h:205 [inline]
 __ip6_local_out+0x3e5/0x890 net/ipv6/output_core.c:166
 ip6_local_out+0x29/0x170 net/ipv6/output_core.c:176
 ip6_send_skb+0xa2/0x330 net/ipv6/ip6_output.c:1688
 udp_v6_send_skb+0x50b/0xee0 net/ipv6/udp.c:1081
 udpv6_sendmsg+0x1eb9/0x2610 net/ipv6/udp.c:1353
 inet_sendmsg+0x122/0x500 net/ipv4/af_inet.c:762
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xce/0x110 net/socket.c:656
 kernel_sendmsg+0x44/0x50 net/socket.c:664
 sock_no_sendpage+0x107/0x130 net/core/sock.c:2569
 kernel_sendpage+0x92/0xf0 net/socket.c:3407
 sock_sendpage+0x8b/0xc0 net/socket.c:871
 pipe_to_sendpage+0x242/0x340 fs/splice.c:451
 splice_from_pipe_feed fs/splice.c:502 [inline]
 __splice_from_pipe+0x348/0x780 fs/splice.c:626
 splice_from_pipe+0xf0/0x150 fs/splice.c:661
 generic_splice_sendpage+0x3c/0x50 fs/splice.c:832
 do_splice_from fs/splice.c:851 [inline]
 do_splice fs/splice.c:1147 [inline]
 SYSC_splice fs/splice.c:1402 [inline]
 SyS_splice+0xd92/0x1430 fs/splice.c:1382
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x448669
RSP: 002b:00007fdd30a5cd98 EFLAGS: 00000246 ORIG_RAX: 0000000000000113
RAX: ffffffffffffffda RBX: 00000000006dec68 RCX: 0000000000448669
RDX: 0000000000000004 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00000000006dec60 R08: 000000011fffffff R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dec6c
R13: 0000000020001440 R14: 00000000004b0c00 R15: 0000000000000000

Allocated by task 7559:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x45/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc mm/kasan/kasan.c:551 [inline]
 kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:529
 __do_kmalloc_node mm/slab.c:3682 [inline]
 __kmalloc_node+0x51/0x80 mm/slab.c:3689
 kmalloc_node include/linux/slab.h:530 [inline]
 kvmalloc_node+0x4e/0xe0 mm/util.c:397
 kvmalloc include/linux/mm.h:531 [inline]
 xt_alloc_table_info+0x71/0xf0 net/netfilter/x_tables.c:1062
 do_replace net/ipv6/netfilter/ip6_tables.c:1146 [inline]
 do_ip6t_set_ctl+0x1eb/0x3f4 net/ipv6/netfilter/ip6_tables.c:1685
 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline]
 nf_setsockopt+0x67/0xc0 net/netfilter/nf_sockopt.c:115
 ipv6_setsockopt net/ipv6/ipv6_sockglue.c:930 [inline]
 ipv6_setsockopt+0x105/0x130 net/ipv6/ipv6_sockglue.c:914
 tcp_setsockopt net/ipv4/tcp.c:2820 [inline]
 tcp_setsockopt+0x84/0xd0 net/ipv4/tcp.c:2814
 sock_common_setsockopt+0x94/0xd0 net/core/sock.c:2968
 SYSC_setsockopt net/socket.c:1865 [inline]
 SyS_setsockopt+0x13c/0x210 net/socket.c:1844
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

Freed by task 5827:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x45/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xcc/0x270 mm/slab.c:3815
 kfree_link+0x16/0x20 fs/libfs.c:1070
 do_delayed_call include/linux/delayed_call.h:28 [inline]
 put_link fs/namei.c:900 [inline]
 step_into fs/namei.c:1787 [inline]
 walk_component+0x3db/0x1d00 fs/namei.c:1844
 link_path_walk+0x4d0/0x10a0 fs/namei.c:2151
 path_openat+0x190/0x3db0 fs/namei.c:3568
 do_filp_open+0x18e/0x250 fs/namei.c:3603
 do_sys_open+0x2c5/0x430 fs/open.c:1084
 SYSC_open fs/open.c:1102 [inline]
 SyS_open+0x2d/0x40 fs/open.c:1097
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

The buggy address belongs to the object at ffff88809417adc0
 which belongs to the cache kmalloc-4096 of size 4096
The buggy address is located 2944 bytes inside of
 4096-byte region [ffff88809417adc0, ffff88809417bdc0)
The buggy address belongs to the page:
page:ffffea0002505e80 count:1 mapcount:0 mapping:ffff88809417adc0 index:0x0 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffff88809417adc0 0000000000000000 0000000100000001
raw: ffffea0001e88b20 ffffea00024f36a0 ffff8880aa800dc0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809417b800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88809417b880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88809417b900: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
                                           ^
 ffff88809417b980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88809417ba00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================