==================================================================
BUG: KASAN: slab-out-of-bounds in strnlen+0xc1/0xd0 lib/string.c:498
Read of size 1 at addr ffff8801d3e7e490 by task syz-executor2/9343

CPU: 1 PID: 9343 Comm: syz-executor2 Not tainted 4.4.113-ge70c132 #27
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 07ef58b5b81ffa29 ffff8800b8377580 ffffffff81d0278d
 ffffea00074f9f80 ffff8801d3e7e490 0000000000000000 ffff8801d3e7e490
 ffff8800b8377850 ffff8800b83775b8 ffffffff814fd053 ffff8801d3e7e490
Call Trace:
 [<ffffffff81d0278d>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d0278d>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
 [<ffffffff814fd053>] print_address_description+0x73/0x260 mm/kasan/report.c:252
 [<ffffffff814fd565>] kasan_report_error mm/kasan/report.c:351 [inline]
 [<ffffffff814fd565>] kasan_report+0x285/0x370 mm/kasan/report.c:408
 [<ffffffff814fd664>] __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:426
 [<ffffffff81d1e171>] strnlen+0xc1/0xd0 lib/string.c:498
 [<ffffffff81d25dfc>] string.isra.4+0x4c/0x240 lib/vsprintf.c:518
 [<ffffffff81d2b2a6>] vsnprintf+0x766/0x15f0 lib/vsprintf.c:1907
 [<ffffffff8117160f>] __request_module+0x14f/0x810 kernel/kmod.c:146
 [<ffffffff8302c64b>] xt_request_find_target+0x8b/0xb0 net/netfilter/x_tables.c:255
 [<ffffffff8326a258>] check_compat_entry_size_and_hooks net/ipv4/netfilter/ip_tables.c:1490 [inline]
 [<ffffffff8326a258>] translate_compat_table+0x568/0x1760 net/ipv4/netfilter/ip_tables.c:1582
 [<ffffffff810002b8>] ? 0xffffffff810002b8
 [<ffffffff8326b641>] compat_do_replace.isra.15+0x1f1/0x410 net/ipv4/netfilter/ip_tables.c:1690
 [<ffffffff8326b966>] compat_do_ipt_set_ctl+0x106/0x150 net/ipv4/netfilter/ip_tables.c:1721
 [<ffffffff82f94e58>] compat_nf_sockopt net/netfilter/nf_sockopt.c:143 [inline]
 [<ffffffff82f94e58>] compat_nf_setsockopt+0x88/0x130 net/netfilter/nf_sockopt.c:155
 [<ffffffff830fc26d>] compat_ip_setsockopt+0x9d/0xf0 net/ipv4/ip_sockglue.c:1255
 [<ffffffff83105455>] inet_csk_compat_setsockopt+0x95/0x120 net/ipv4/inet_connection_sock.c:914
 [<ffffffff8311acbd>] compat_tcp_setsockopt+0x3d/0x70 net/ipv4/tcp.c:2643
 [<ffffffff82df0732>] compat_sock_common_setsockopt+0xb2/0x140 net/core/sock.c:2670
 [<ffffffff82ed7659>] C_SYSC_setsockopt net/compat.c:384 [inline]
 [<ffffffff82ed7659>] compat_SyS_setsockopt+0x149/0x290 net/compat.c:367
 [<ffffffff81006d74>] do_syscall_32_irqs_on arch/x86/entry/common.c:390 [inline]
 [<ffffffff81006d74>] do_fast_syscall_32+0x314/0x890 arch/x86/entry/common.c:457
 [<ffffffff837734ea>] sysenter_flags_fixed+0xd/0x17

Allocated by task 9343:
 [<ffffffff81035df6>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff814fc0c3>] save_stack+0x43/0xd0 mm/kasan/kasan.c:512
 [<ffffffff814fc38d>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff814fc38d>] kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:616
 [<ffffffff814f8674>] __kmalloc+0x124/0x320 mm/slub.c:3613
 [<ffffffff8302de91>] kmalloc include/linux/slab.h:481 [inline]
 [<ffffffff8302de91>] xt_alloc_table_info+0x71/0x100 net/netfilter/x_tables.c:911
 [<ffffffff8326b5bb>] compat_do_replace.isra.15+0x16b/0x410 net/ipv4/netfilter/ip_tables.c:1679
 [<ffffffff8326b966>] compat_do_ipt_set_ctl+0x106/0x150 net/ipv4/netfilter/ip_tables.c:1721
 [<ffffffff82f94e58>] compat_nf_sockopt net/netfilter/nf_sockopt.c:143 [inline]
 [<ffffffff82f94e58>] compat_nf_setsockopt+0x88/0x130 net/netfilter/nf_sockopt.c:155
 [<ffffffff830fc26d>] compat_ip_setsockopt+0x9d/0xf0 net/ipv4/ip_sockglue.c:1255
 [<ffffffff83105455>] inet_csk_compat_setsockopt+0x95/0x120 net/ipv4/inet_connection_sock.c:914
 [<ffffffff8311acbd>] compat_tcp_setsockopt+0x3d/0x70 net/ipv4/tcp.c:2643
 [<ffffffff82df0732>] compat_sock_common_setsockopt+0xb2/0x140 net/core/sock.c:2670
 [<ffffffff82ed7659>] C_SYSC_setsockopt net/compat.c:384 [inline]
 [<ffffffff82ed7659>] compat_SyS_setsockopt+0x149/0x290 net/compat.c:367
 [<ffffffff81006d74>] do_syscall_32_irqs_on arch/x86/entry/common.c:390 [inline]
 [<ffffffff81006d74>] do_fast_syscall_32+0x314/0x890 arch/x86/entry/common.c:457
 [<ffffffff837734ea>] sysenter_flags_fixed+0xd/0x17

Freed by task 4891:
 [<ffffffff81035df6>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff814fc0c3>] save_stack+0x43/0xd0 mm/kasan/kasan.c:512
 [<ffffffff814fc9e2>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff814fc9e2>] kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:589
 [<ffffffff814f947c>] slab_free_hook mm/slub.c:1383 [inline]
 [<ffffffff814f947c>] slab_free_freelist_hook mm/slub.c:1405 [inline]
 [<ffffffff814f947c>] slab_free mm/slub.c:2859 [inline]
 [<ffffffff814f947c>] kfree+0xfc/0x300 mm/slub.c:3749
 [<ffffffff8158d3d0>] seq_release fs/seq_file.c:372 [inline]
 [<ffffffff8158d3d0>] single_release+0x80/0xb0 fs/seq_file.c:608
 [<ffffffff81665322>] close_pdeo+0xf2/0x230 fs/proc/inode.c:153
 [<ffffffff8166558b>] proc_reg_release+0x12b/0x170 fs/proc/inode.c:359
 [<ffffffff81522363>] __fput+0x233/0x6d0 fs/file_table.c:208
 [<ffffffff81522885>] ____fput+0x15/0x20 fs/file_table.c:244
 [<ffffffff8118b9d4>] task_work_run+0x104/0x180 kernel/task_work.c:115
 [<ffffffff8100361d>] tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 [<ffffffff8100361d>] exit_to_usermode_loop+0x13d/0x160 arch/x86/entry/common.c:251
 [<ffffffff81006535>] prepare_exit_to_usermode arch/x86/entry/common.c:282 [inline]
 [<ffffffff81006535>] syscall_return_slowpath+0x1b5/0x1f0 arch/x86/entry/common.c:347
 [<ffffffff83771ce9>] int_ret_from_sys_call+0x25/0xa3

The buggy address belongs to the object at ffff8801d3e7e3c0
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 208 bytes inside of
 256-byte region [ffff8801d3e7e3c0, ffff8801d3e7e4c0)
The buggy address belongs to the page:
------------[ cut here ]------------
WARNING: CPU: 0 PID: -1209158496 at kernel/locking/lockdep.c:3123 __lock_acquire+0x1625/0x4b50 kernel/locking/lockdep.c:3123()
DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)