IPVS: set_ctl: invalid protocol: 63 172.20.20.170:20000 sh
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BUG: KASAN: stack-out-of-bounds in strnlen+0xc1/0xd0 lib/string.c:498
Read of size 1 at addr ffff8801d49a7c84 by task syz-executor6/9060

CPU: 1 PID: 9060 Comm: syz-executor6 Not tainted 4.4.138-gcf21a9a #64
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 c581e69c512864ba ffff8801d49a76f0 ffffffff81e0ed0d
 ffffea00075269c0 ffff8801d49a7c84 0000000000000000 ffff8801d49a7c84
 ffff8801d49a7c50 ffff8801d49a7728 ffffffff81515a16 ffff8801d49a7c84
Call Trace:
 [<ffffffff81e0ed0d>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81e0ed0d>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
 [<ffffffff81515a16>] print_address_description+0x6c/0x216 mm/kasan/report.c:252
 [<ffffffff81515d35>] kasan_report_error mm/kasan/report.c:351 [inline]
 [<ffffffff81515d35>] kasan_report.cold.7+0x175/0x2f7 mm/kasan/report.c:408
 [<ffffffff814f97c4>] __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:426
 [<ffffffff81e2a811>] strnlen+0xc1/0xd0 lib/string.c:498
 [<ffffffff81e328fc>] string.isra.4+0x4c/0x250 lib/vsprintf.c:518
 [<ffffffff81e37ab2>] vsnprintf+0x402/0x18e0 lib/vsprintf.c:1907
 [<ffffffff81e38fbd>] vscnprintf+0x2d/0x60 lib/vsprintf.c:2010
 [<ffffffff8125d0df>] vprintk_emit+0xdf/0x840 kernel/printk/printk.c:1729
 [<ffffffff8125d868>] vprintk+0x28/0x30 kernel/printk/printk.c:1843
 [<ffffffff8125d88d>] vprintk_default+0x1d/0x30 kernel/printk/printk.c:1844
 [<ffffffff81415328>] printk+0xaf/0xd7 kernel/printk/printk.c:1922
 [<ffffffff8389e264>] do_ip_vs_set_ctl.cold.37+0x32/0x37 net/netfilter/ipvs/ip_vs_ctl.c:2394
 [<ffffffff830c6bed>] nf_sockopt net/netfilter/nf_sockopt.c:105 [inline]
 [<ffffffff830c6bed>] nf_setsockopt+0x6d/0xc0 net/netfilter/nf_sockopt.c:114
 [<ffffffff8322696a>] ip_setsockopt+0x9a/0xb0 net/ipv4/ip_sockglue.c:1225
 [<ffffffff832cbcfa>] udp_setsockopt+0x4a/0x90 net/ipv4/udp.c:2162
 [<ffffffff834838da>] ipv6_setsockopt+0x10a/0x130 net/ipv6/ipv6_sockglue.c:899
 [<ffffffff83244408>] tcp_setsockopt+0x88/0xe0 net/ipv4/tcp.c:2643
 [<ffffffff82f248ba>] sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:2659
 [<ffffffff82f217d6>] SYSC_setsockopt net/socket.c:1767 [inline]
 [<ffffffff82f217d6>] SyS_setsockopt+0x166/0x260 net/socket.c:1746
 [<ffffffff838c2725>] entry_SYSCALL_64_fastpath+0x22/0x9e

The buggy address belongs to the page:
page:ffffea00075269c0 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x8000000000000000()
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d49a7b80: 00 00 00 00 00 04 f2 f2 f2 f2 f2 f2 00 00 00 00
 ffff8801d49a7c00: 00 00 00 00 f2 f2 f2 f2 00 00 00 00 00 00 00 00
>ffff8801d49a7c80: 04 f2 f2 f2 00 00 00 00 00 00 00 00 00 00 00 00
                   ^
 ffff8801d49a7d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801d49a7d80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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