syzbot

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BUG: KASAN: global-out-of-bounds in fib6_clean_node+0x3a6/0x5e0
Read of size 8 at addr ffffffff9aa21228 by task syz.7.863/9756

CPU: 1 UID: 0 PID: 9756 Comm: syz.7.863 Not tainted 6.14.0-rc6-syzkaller-00022-gb7f94fcf5546 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0x16e/0x5b0 mm/kasan/report.c:521
 kasan_report+0x143/0x180 mm/kasan/report.c:634
 fib6_clean_node+0x3a6/0x5e0
 fib6_walk_continue+0x65a/0x8f0 net/ipv6/ip6_fib.c:2124
 fib6_walk+0x168/0x2b0 net/ipv6/ip6_fib.c:2172
 fib6_clean_tree net/ipv6/ip6_fib.c:2252 [inline]
 __fib6_clean_all+0x31f/0x4b0 net/ipv6/ip6_fib.c:2268
 rt6_sync_down_dev net/ipv6/route.c:4913 [inline]
 rt6_disable_ip+0x170/0x800 net/ipv6/route.c:4918
 addrconf_ifdown+0x15d/0x1b00 net/ipv6/addrconf.c:3849
 addrconf_notify+0x3cb/0x1020
 notifier_call_chain+0x1a7/0x3f0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2244 [inline]
 call_netdevice_notifiers net/core/dev.c:2258 [inline]
 dev_close_many+0x33c/0x4c0 net/core/dev.c:1748
 unregister_netdevice_many_notify+0x52d/0x1f10 net/core/dev.c:11856
 rtnl_delete_link net/core/rtnetlink.c:3486 [inline]
 rtnl_dellink+0x52b/0x8d0 net/core/rtnetlink.c:3528
 rtnetlink_rcv_msg+0x793/0xcf0 net/core/rtnetlink.c:6912
 netlink_rcv_skb+0x208/0x480 net/netlink/af_netlink.c:2533
 netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline]
 netlink_unicast+0x7f8/0x990 net/netlink/af_netlink.c:1338
 netlink_sendmsg+0x8de/0xcb0 net/netlink/af_netlink.c:1882
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg+0x223/0x270 net/socket.c:733
 ____sys_sendmsg+0x53a/0x860 net/socket.c:2573
 ___sys_sendmsg net/socket.c:2627 [inline]
 __sys_sendmsg+0x269/0x350 net/socket.c:2659
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3a7398d169
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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f3a748b1038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f3a73ba5fa0 RCX: 00007f3a7398d169
RDX: 0000000000000000 RSI: 0000400000000100 RDI: 0000000000000005
RBP: 00007f3a73a0e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f3a73ba5fa0 R15: 00007ffd2d8376c8
 </TASK>

The buggy address belongs to the variable:
 binder_devices+0x8/0x20

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1aa21
flags: 0xfff00000002000(reserved|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000002000 ffffea00006a8848 ffffea00006a8848 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:
 ffffffff9aa21100: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
 ffffffff9aa21180: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
>ffffffff9aa21200: f9 f9 f9 f9 00 f9 f9 f9 00 00 f9 f9 00 00 00 00
                                  ^
 ffffffff9aa21280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffffff9aa21300: 00 00 00 00 00 00 00 00 00 00 04 f9 f9 f9 f9 f9
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