==================================================================
BUG: KASAN: slab-out-of-bounds in strnlen+0xc1/0xd0 lib/string.c:498
Read of size 1 at addr ffff8801d991e49e by task syz-executor7/20518

CPU: 1 PID: 20518 Comm: syz-executor7 Not tainted 4.4.113-gef588ef #26
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 6b696dc995225a2d ffff8800b40b7580 ffffffff81d0278d
 ffffea0007664780 ffff8801d991e49e 0000000000000000 ffff8801d991e49e
 ffff8800b40b7850 ffff8800b40b75b8 ffffffff814fd053 ffff8801d991e49e
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 20518:
 [<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 8772:
 [<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
 [<ffffffff816761ae>] free_proc_entry fs/proc/generic.c:535 [inline]
 [<ffffffff816761ae>] pde_put+0x8e/0xe0 fs/proc/generic.c:541
 [<ffffffff81676a7d>] remove_proc_entry+0x1dd/0x310 fs/proc/generic.c:577
 [<ffffffff8322c246>] ipmr_net_exit+0x46/0x120 net/ipv4/ipmr.c:2739
 [<ffffffff82e292be>] ops_exit_list.isra.4+0xae/0x150 net/core/net_namespace.c:134
 [<ffffffff82e2c26d>] cleanup_net+0x31d/0x5f0 net/core/net_namespace.c:433
 [<ffffffff8117fd87>] process_one_work+0x7d7/0x16e0 kernel/workqueue.c:2064
 [<ffffffff81180d69>] worker_thread+0xd9/0xfc0 kernel/workqueue.c:2196
 [<ffffffff811907d8>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff83771f85>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:506

The buggy address belongs to the object at ffff8801d991e3c0
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 222 bytes inside of
 256-byte region [ffff8801d991e3c0, ffff8801d991e4c0)
The buggy address belongs to the page:
syz-fuzzer: Corrupted page table at address 45ddf3
PGD 80000000b5110067 PUD b6ab7067 PMD b1a54067 PTE ffffffff8148f8e1
Bad pagetable: 001d [#1] PREEMPT SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 3326 Comm: syz-fuzzer Not tainted 4.4.113-gef588ef #26
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800b4c8df00 task.stack: ffff8801d0788000
RIP: 0033:[<000000000045ddf3>]  [<000000000045ddf3>] 0x45ddf3
RSP: 002b:000000c420025ea0  EFLAGS: 00010206
RAX: ffffffffffffff92 RBX: 000000003b986c5a RCX: 000000000045ddf3
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001904560
RBP: 000000c420025ee8 R08: 0000000000000000 R09: 0000000000000000
R10: 000000c420025ed8 R11: 0000000000000206 R12: 0000000000000001
R13: 00000000000000ff R14: 00000000000000ff R15: 0000000000000000
FS:  000000c42005cae8(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000045ddf3 CR3: 00000000b44da000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

RIP  [<000000000045ddf3>] 0x45ddf3
 RSP <000000c420025ea0>
---[ end trace 363a59a9dcf8f8ad ]---