==================================================================
BUG: KASAN: slab-out-of-bounds in dns_resolver_preparse+0x910/0x9b0 net/dns_resolver/dns_key.c:127
Read of size 1 at addr ffff888017fa643c by task syz-executor.3/5060

CPU: 0 PID: 5060 Comm: syz-executor.3 Not tainted 5.10.206 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x107/0x167 lib/dump_stack.c:118
 print_address_description.constprop.0+0x1c/0x220 mm/kasan/report.c:377
 __kasan_report mm/kasan/report.c:537 [inline]
 kasan_report.cold+0x37/0x7c mm/kasan/report.c:554
 dns_resolver_preparse+0x910/0x9b0 net/dns_resolver/dns_key.c:127
 key_create_or_update+0x3e0/0xc30 security/keys/key.c:859
 __do_sys_add_key+0x215/0x430 security/keys/keyctl.c:134
 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x62/0xc7
RIP: 0033:0x7f62cee39b19
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f62cc3af188 EFLAGS: 00000246 ORIG_RAX: 00000000000000f8
RAX: ffffffffffffffda RBX: 00007f62cef4cf60 RCX: 00007f62cee39b19
RDX: 0000000020000000 RSI: 0000000000000000 RDI: 0000000020000200
RBP: 00007f62cee93f6d R08: fffffffffffffffb R09: 0000000000000000
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffec52e3e2f R14: 00007f62cc3af300 R15: 0000000000022000

Allocated by task 5060:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xc9/0xd0 mm/kasan/common.c:461
 kmalloc_node include/linux/slab.h:575 [inline]
 kvmalloc_node+0x119/0x170 mm/util.c:607
 kvmalloc include/linux/mm.h:765 [inline]
 __do_sys_add_key+0x311/0x430 security/keys/keyctl.c:116
 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x62/0xc7

The buggy address belongs to the object at ffff888017fa6438
 which belongs to the cache kmalloc-8 of size 8
The buggy address is located 4 bytes inside of
 8-byte region [ffff888017fa6438, ffff888017fa6440)
The buggy address belongs to the page:
page:000000004f11d502 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x17fa6
flags: 0x100000000000200(slab)
raw: 0100000000000200 ffffea0000548600 0000000500000005 ffff888008041c80
raw: 0000000000000000 0000000080660066 00000001ffffffff ffff88801ac01801
page dumped because: kasan: bad access detected
page->mem_cgroup:ffff88801ac01801

Memory state around the buggy address:
 ffff888017fa6300: fc fc fc fc fb fc fc fc fc 00 fc fc fc fc fa fc
 ffff888017fa6380: fc fc fc fa fc fc fc fc fa fc fc fc fc fa fc fc
>ffff888017fa6400: fc fc 04 fc fc fc fc 04 fc fc fc fc fb fc fc fc
                                        ^
 ffff888017fa6480: fc fb fc fc fc fc fb fc fc fc fc fb fc fc fc fc
 ffff888017fa6500: fb fc fc fc fc fb fc fc fc fc fb fc fc fc fc fb
==================================================================
9pnet: Insufficient options for proto=fd
EXT4-fs (sda): re-mounted. Opts: (null)
EXT4-fs (sda): re-mounted. Opts: (null)