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BUG: KASAN: global-out-of-bounds in fib6_ifdown+0x7f5/0x8f0 net/ipv6/route.c:4863
Read of size 8 at addr ffffffff9ac27510 by task kworker/u32:9/1181

CPU: 2 UID: 0 PID: 1181 Comm: kworker/u32:9 Not tainted 6.14.0-rc6-syzkaller-00016-g0fed89a961ea #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: netns cleanup_net
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+0xd9/0x110 mm/kasan/report.c:634
 fib6_ifdown+0x7f5/0x8f0 net/ipv6/route.c:4863
 fib6_clean_node+0x2a5/0x5b0 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+0xd7/0x120 net/ipv6/ip6_fib.c:2252
 __fib6_clean_all+0x100/0x2d0 net/ipv6/ip6_fib.c:2268
 rt6_sync_down_dev net/ipv6/route.c:4913 [inline]
 rt6_disable_ip+0x2ef/0x940 net/ipv6/route.c:4918
 addrconf_ifdown.isra.0+0x126/0x1af0 net/ipv6/addrconf.c:3849
 addrconf_notify+0x220/0x19c0 net/ipv6/addrconf.c:3772
 notifier_call_chain+0xb7/0x410 kernel/notifier.c:85
 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2206
 call_netdevice_notifiers_extack net/core/dev.c:2244 [inline]
 call_netdevice_notifiers net/core/dev.c:2258 [inline]
 dev_close_many+0x333/0x6a0 net/core/dev.c:1748
 unregister_netdevice_many_notify+0x48a/0x1f30 net/core/dev.c:11856
 unregister_netdevice_many net/core/dev.c:11948 [inline]
 unregister_netdevice_queue+0x307/0x3f0 net/core/dev.c:11818
 unregister_netdevice include/linux/netdevice.h:3337 [inline]
 nsim_destroy+0x135/0x710 drivers/net/netdevsim/netdev.c:1021
 __nsim_dev_port_del+0x189/0x240 drivers/net/netdevsim/dev.c:1428
 nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1440 [inline]
 nsim_dev_reload_destroy+0x108/0x4d0 drivers/net/netdevsim/dev.c:1661
 nsim_dev_reload_down+0x6e/0xd0 drivers/net/netdevsim/dev.c:968
 devlink_reload+0x19a/0x7c0 net/devlink/dev.c:461
 devlink_pernet_pre_exit+0x1a1/0x2b0 net/devlink/core.c:509
 ops_pre_exit_list net/core/net_namespace.c:162 [inline]
 cleanup_net+0x497/0xb30 net/core/net_namespace.c:632
 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3400
 kthread+0x3af/0x750 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </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:0x1ac27
flags: 0xfff00000002000(reserved|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000002000 ffffea00006b09c8 ffffea00006b09c8 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:
 ffffffff9ac27400: f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9 00 f9 f9 f9
 ffffffff9ac27480: f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9 00 00 f9 f9
>ffffffff9ac27500: f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9 00 00 00 00
                         ^
 ffffffff9ac27580: 00 00 00 00 00 00 00 00 00 00 00 f9 f9 f9 f9 f9
 ffffffff9ac27600: 00 00 f9 f9 f9 f9 f9 f9 00 00 f9 f9 f9 f9 f9 f9
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