audit: type=1400 audit(1516826028.834:7): avc:  denied  { map } for  pid=3662 comm="syzkaller922216" path="/root/syzkaller922216162" dev="sda1" ino=16481 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1
==================================================================
BUG: KASAN: slab-out-of-bounds in string+0x1e8/0x200 lib/vsprintf.c:595
Read of size 1 at addr ffff8801d9a90ed0 by task syzkaller922216/3662

CPU: 1 PID: 3662 Comm: syzkaller922216 Not tainted 4.15.0-rc9+ #188
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
 compat_udp_setsockopt+0x45/0x80 net/ipv4/udp.c:2418
 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: 0023:0xf7fd8c79
RSP: 002b:00000000ffd0661c EFLAGS: 00000282 ORIG_RAX: 000000000000016e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000000000
RDX: 0000000000000040 RSI: 0000000020f20000 RDI: 00000000000000f0
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 3662:
 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
 compat_udp_setsockopt+0x45/0x80 net/ipv4/udp.c:2418
 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 2015:
 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
 seq_release fs/seq_file.c:366 [inline]
 single_release+0x80/0xb0 fs/seq_file.c:602
 __fput+0x327/0x7e0 fs/file_table.c:210
 ____fput+0x15/0x20 fs/file_table.c:244
 task_work_run+0x199/0x270 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x296/0x310 arch/x86/entry/common.c:162
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath+0x490/0x550 arch/x86/entry/common.c:264
 entry_SYSCALL_64_fastpath+0x9e/0xa0

The buggy address belongs to the object at ffff8801d9a90e00
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 208 bytes inside of
 256-byte region [ffff8801d9a90e00, ffff8801d9a90f00)
The buggy address belongs to the page:
page:ffffea000766a400 count:1 mapcount:0 mapping:ffff8801d9a90040 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801d9a90040 0000000000000000 000000010000000c
raw: ffffea000766cca0 ffffea0007654120 ffff8801dac007c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d9a90d80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff8801d9a90e00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8801d9a90e80: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
                                                 ^
 ffff8801d9a90f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801d9a90f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================