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BUG: KASAN: global-out-of-bounds in fib6_add_rt2node net/ipv6/ip6_fib.c:1102 [inline]
BUG: KASAN: global-out-of-bounds in fib6_add+0x3ced/0x4b60 net/ipv6/ip6_fib.c:1488
Read of size 4 at addr ffffffff9af9f590 by task dhcpcd/5651

CPU: 3 UID: 0 PID: 5651 Comm: dhcpcd Not tainted 6.15.0-rc7-syzkaller-00152-gd0c22de9995b #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_add_rt2node net/ipv6/ip6_fib.c:1102 [inline]
 fib6_add+0x3ced/0x4b60 net/ipv6/ip6_fib.c:1488
 __ip6_ins_rt net/ipv6/route.c:1351 [inline]
 ip6_route_add+0x8d/0x1c0 net/ipv6/route.c:3900
 addrconf_add_mroute+0x1dd/0x350 net/ipv6/addrconf.c:2551
 addrconf_add_dev+0x14e/0x1c0 net/ipv6/addrconf.c:2569
 addrconf_dev_config net/ipv6/addrconf.c:3477 [inline]
 addrconf_init_auto_addrs+0x3f3/0x8f0 net/ipv6/addrconf.c:3571
 addrconf_notify+0xe93/0x19e0 net/ipv6/addrconf.c:3744
 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_notify_flags+0x12c/0x2e0 net/core/dev.c:9393
 netif_change_flags+0x108/0x160 net/core/dev.c:9422
 dev_change_flags+0xba/0x250 net/core/dev_api.c:68
 devinet_ioctl+0x11d5/0x1f50 net/ipv4/devinet.c:1200
 inet_ioctl+0x3a7/0x3f0 net/ipv4/af_inet.c:1001
 sock_do_ioctl+0x115/0x280 net/socket.c:1190
 sock_ioctl+0x227/0x6b0 net/socket.c:1311
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl fs/ioctl.c:892 [inline]
 __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f81b25b3378
Code: 00 00 48 8d 44 24 08 48 89 54 24 e0 48 89 44 24 c0 48 8d 44 24 d0 48 89 44 24 c8 b8 10 00 00 00 c7 44 24 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 07 89 d0 c3 0f 1f 40 00 48 8b 15 49 3a 0d
RSP: 002b:00007fff16644368 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000000002c RCX: 00007f81b25b3378
RDX: 00007fff16654560 RSI: 0000000000008914 RDI: 000000000000002c
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff16664700
R13: 00007f81b24b36c8 R14: 0000000000000028 R15: 0000000000008914
 </TASK>

The buggy address belongs to the variable:
 __key.0+0x10/0x40

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1af9f
flags: 0xfff00000002000(reserved|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000002000 ffffea00006be7c8 ffffea00006be7c8 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:
 ffffffff9af9f480: 00 f9 f9 f9 f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9
 ffffffff9af9f500: 00 f9 f9 f9 f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9
>ffffffff9af9f580: 00 00 f9 f9 f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9
                         ^
 ffffffff9af9f600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f9
 ffffffff9af9f680: f9 f9 f9 f9 00 00 f9 f9 f9 f9 f9 f9 00 00 f9 f9
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