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BUG: KASAN: slab-out-of-bounds in string+0x1e8/0x200 lib/vsprintf.c:595
Read of size 1 at addr ffff8801cd890750 by task syz-executor1/5827

CPU: 1 PID: 5827 Comm: syz-executor1 Not tainted 4.15.0-rc9+ #192
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:2886
 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: 0023:0xf7f68c79
RSP: 002b:00000000f776408c 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 5827:
 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:2886
 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 3738:
 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
 free_bprm+0x19d/0x200 fs/exec.c:1414
 do_execveat_common.isra.30+0x1a24/0x23c0 fs/exec.c:1812
 do_execve fs/exec.c:1847 [inline]
 SYSC_execve fs/exec.c:1928 [inline]
 SyS_execve+0x39/0x50 fs/exec.c:1923
 do_syscall_64+0x273/0x920 arch/x86/entry/common.c:285
 return_from_SYSCALL_64+0x0/0x75

The buggy address belongs to the object at ffff8801cd890680
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 208 bytes inside of
 256-byte region [ffff8801cd890680, ffff8801cd890780)
The buggy address belongs to the page:
page:ffffea0007362400 count:1 mapcount:0 mapping:ffff8801cd890040 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801cd890040 0000000000000000 000000010000000c
raw: ffffea0007350de0 ffffea0007351020 ffff8801dac007c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801cd890600: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801cd890680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8801cd890700: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
                                                 ^
 ffff8801cd890780: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff8801cd890800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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