==================================================================
BUG: KASAN: global-out-of-bounds in fib6_ifdown+0x7f5/0x8f0 net/ipv6/route.c:4901
Read of size 8 at addr ffffffff9af83c90 by task syz.4.1252/10927

CPU: 1 UID: 0 PID: 10927 Comm: syz.4.1252 Not tainted 6.15.0-rc6-syzkaller-00208-g3c21441eeffc #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xc3/0x670 mm/kasan/report.c:521
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 fib6_ifdown+0x7f5/0x8f0 net/ipv6/route.c:4901
 fib6_clean_node+0x2a4/0x5b0 net/ipv6/ip6_fib.c:2199
 fib6_walk_continue+0x44f/0x8d0 net/ipv6/ip6_fib.c:2124
 fib6_walk+0x182/0x370 net/ipv6/ip6_fib.c:2172
 fib6_clean_tree+0xd4/0x110 net/ipv6/ip6_fib.c:2252
 __fib6_clean_all+0x107/0x2d0 net/ipv6/ip6_fib.c:2268
 rt6_sync_down_dev net/ipv6/route.c:4951 [inline]
 rt6_disable_ip+0x2ec/0x990 net/ipv6/route.c:4956
 addrconf_ifdown.isra.0+0x11d/0x1a90 net/ipv6/addrconf.c:3857
 addrconf_notify+0x220/0x19e0 net/ipv6/addrconf.c:3780
 notifier_call_chain+0xbc/0x410 kernel/notifier.c:85
 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2176
 call_netdevice_notifiers_extack net/core/dev.c:2214 [inline]
 call_netdevice_notifiers net/core/dev.c:2228 [inline]
 dev_close_many+0x319/0x630 net/core/dev.c:1731
 netif_close net/core/dev.c:1744 [inline]
 netif_close+0x17f/0x230 net/core/dev.c:1738
 dev_close+0xaa/0x240 net/core/dev_api.c:219
 cfg80211_shutdown_all_interfaces+0x9a/0x200 net/wireless/core.c:277
 cfg80211_rfkill_set_block net/wireless/core.c:307 [inline]
 cfg80211_rfkill_set_block+0x35/0x50 net/wireless/core.c:299
 rfkill_set_block+0x1fb/0x550 net/rfkill/core.c:346
 rfkill_fop_write+0x2c0/0x580 net/rfkill/core.c:1301
 vfs_write+0x25c/0x1180 fs/read_write.c:682
 ksys_write+0x205/0x240 fs/read_write.c:736
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0x73/0x120 arch/x86/entry/syscall_32.c:306
 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:331
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf703e579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f4fec55c EFLAGS: 00000296 ORIG_RAX: 0000000000000004
RAX: ffffffffffffffda RBX: 000000000000000c RCX: 0000000080000080
RDX: 0000000000000008 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

The buggy address belongs to the variable:
 __key.0+0x30/0x40

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1af83
flags: 0xfff00000002000(reserved|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000002000 ffffea00006be0c8 ffffea00006be0c8 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner info is not present (never set?)

Memory state around the buggy address:
 ffffffff9af83b80: f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9 00 f9 f9 f9
 ffffffff9af83c00: f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9 00 00 f9 f9
>ffffffff9af83c80: f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9 00 00 00 00
                         ^
 ffffffff9af83d00: 00 00 00 00 00 00 00 00 00 00 00 f9 f9 f9 f9 f9
 ffffffff9af83d80: 00 00 f9 f9 f9 f9 f9 f9 00 00 f9 f9 f9 f9 f9 f9
==================================================================
----------------
Code disassembly (best guess), 2 bytes skipped:
   0:	10 06                	adc    %al,(%rsi)
   2:	03 74 b4 01          	add    0x1(%rsp,%rsi,4),%esi
   6:	10 07                	adc    %al,(%rdi)
   8:	03 74 b0 01          	add    0x1(%rax,%rsi,4),%esi
   c:	10 08                	adc    %cl,(%rax)
   e:	03 74 d8 01          	add    0x1(%rax,%rbx,8),%esi
  1e:	00 51 52             	add    %dl,0x52(%rcx)
  21:	55                   	push   %rbp
  22:	89 e5                	mov    %esp,%ebp
  24:	0f 34                	sysenter
  26:	cd 80                	int    $0x80
* 28:	5d                   	pop    %rbp <-- trapping instruction
  29:	5a                   	pop    %rdx
  2a:	59                   	pop    %rcx
  2b:	c3                   	ret
  2c:	90                   	nop
  2d:	90                   	nop
  2e:	90                   	nop
  2f:	90                   	nop
  30:	8d b4 26 00 00 00 00 	lea    0x0(%rsi,%riz,1),%esi
  37:	8d b4 26 00 00 00 00 	lea    0x0(%rsi,%riz,1),%esi