==================================================================
BUG: KASAN: slab-out-of-bounds in string+0x1e8/0x200 lib/vsprintf.c:595
Read of size 1 at addr ffff8801c344d890 by task syz-executor2/18807

CPU: 0 PID: 18807 Comm: syz-executor2 Not tainted 4.15.0-rc9+ #191
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+0x194/0x257 lib/dump_stack.c:53
 print_address_description+0x73/0x250 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report+0x25b/0x340 mm/kasan/report.c:409
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:427
 string+0x1e8/0x200 lib/vsprintf.c:595
 vsnprintf+0x863/0x1900 lib/vsprintf.c:2282
 __request_module+0x1bf/0xc20 kernel/kmod.c:143
 xt_request_find_target+0x8b/0xb0 net/netfilter/x_tables.c:257
 check_compat_entry_size_and_hooks net/ipv4/netfilter/ip_tables.c:1339 [inline]
 translate_compat_table+0x910/0x1b90 net/ipv4/netfilter/ip_tables.c:1426
 compat_do_replace.isra.15+0x30e/0x720 net/ipv4/netfilter/ip_tables.c:1529
 compat_do_ipt_set_ctl+0x106/0x150 net/ipv4/netfilter/ip_tables.c:1558
 compat_nf_sockopt net/netfilter/nf_sockopt.c:144 [inline]
 compat_nf_setsockopt+0x88/0x130 net/netfilter/nf_sockopt.c:156
 compat_ip_setsockopt+0x9d/0xf0 net/ipv4/ip_sockglue.c:1285
 inet_csk_compat_setsockopt+0x95/0x120 net/ipv4/inet_connection_sock.c:1042
 compat_tcp_setsockopt+0x3d/0x70 net/ipv4/tcp.c:2883
 compat_sock_common_setsockopt+0xb2/0x140 net/core/sock.c:2979
 C_SYSC_setsockopt net/compat.c:403 [inline]
 compat_SyS_setsockopt+0x17c/0x410 net/compat.c:386
 do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline]
 do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389
 entry_SYSENTER_compat+0x54/0x63 arch/x86/entry/entry_64_compat.S:129
RIP: 0023:0xf7f62c79
RSP: 002b:00000000f775e08c EFLAGS: 00000296 ORIG_RAX: 000000000000016e
RAX: ffffffffffffffda RBX: 0000000000000013 RCX: 0000000000000000
RDX: 0000000000000040 RSI: 000000002016b000 RDI: 00000000000000ec
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 18807:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551
 __do_kmalloc_node mm/slab.c:3672 [inline]
 __kmalloc_node+0x47/0x70 mm/slab.c:3679
 kmalloc_node include/linux/slab.h:541 [inline]
 kvmalloc_node+0x99/0xd0 mm/util.c:397
 kvmalloc include/linux/mm.h:541 [inline]
 xt_alloc_table_info+0x64/0xe0 net/netfilter/x_tables.c:1006
 compat_do_replace.isra.15+0x17f/0x720 net/ipv4/netfilter/ip_tables.c:1518
 compat_do_ipt_set_ctl+0x106/0x150 net/ipv4/netfilter/ip_tables.c:1558
 compat_nf_sockopt net/netfilter/nf_sockopt.c:144 [inline]
 compat_nf_setsockopt+0x88/0x130 net/netfilter/nf_sockopt.c:156
 compat_ip_setsockopt+0x9d/0xf0 net/ipv4/ip_sockglue.c:1285
 inet_csk_compat_setsockopt+0x95/0x120 net/ipv4/inet_connection_sock.c:1042
 compat_tcp_setsockopt+0x3d/0x70 net/ipv4/tcp.c:2883
 compat_sock_common_setsockopt+0xb2/0x140 net/core/sock.c:2979
 C_SYSC_setsockopt net/compat.c:403 [inline]
 compat_SyS_setsockopt+0x17c/0x410 net/compat.c:386
 do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline]
 do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389
 entry_SYSENTER_compat+0x54/0x63 arch/x86/entry/entry_64_compat.S:129

Freed by task 15269:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3488 [inline]
 kfree+0xd6/0x260 mm/slab.c:3803
 iter_file_splice_write+0x6af/0xf30 fs/splice.c:776
 do_splice_from fs/splice.c:851 [inline]
 direct_splice_actor+0x125/0x180 fs/splice.c:1018
 splice_direct_to_actor+0x2c1/0x820 fs/splice.c:973
 do_splice_direct+0x29b/0x3c0 fs/splice.c:1061
 do_sendfile+0x5c9/0xe80 fs/read_write.c:1413
 C_SYSC_sendfile fs/read_write.c:1489 [inline]
 compat_SyS_sendfile+0xea/0x1a0 fs/read_write.c:1478
 do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline]
 do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389
 entry_SYSENTER_compat+0x54/0x63 arch/x86/entry/entry_64_compat.S:129

The buggy address belongs to the object at ffff8801c344d7c0
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 208 bytes inside of
 256-byte region [ffff8801c344d7c0, ffff8801c344d8c0)
The buggy address belongs to the page:
page:ffffea00070d1340 count:1 mapcount:0 mapping:ffff8801c344d040 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801c344d040 0000000000000000 000000010000000c
raw: ffffea000712a360 ffffea00070911a0 ffff8801dac007c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801c344d780: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
 ffff8801c344d800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8801c344d880: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                         ^
 ffff8801c344d900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801c344d980: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
==================================================================