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BUG: KASAN: use-after-free in __fib6_clean_all+0x296/0x2a0 net/ipv6/ip6_fib.c:2255
Read of size 8 at addr ffff888067149000 by task syz-executor.3/5781

CPU: 0 PID: 5781 Comm: syz-executor.3 Not tainted 5.18.0-rc7-syzkaller-00164-g6c3f5bec9b40 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description.constprop.0.cold+0xeb/0x467 mm/kasan/report.c:313
 print_report mm/kasan/report.c:429 [inline]
 kasan_report.cold+0xf4/0x1c6 mm/kasan/report.c:491
 __fib6_clean_all+0x296/0x2a0 net/ipv6/ip6_fib.c:2255
 rt6_sync_down_dev net/ipv6/route.c:4883 [inline]
 rt6_disable_ip+0x7b7/0x9a0 net/ipv6/route.c:4888
 addrconf_ifdown.isra.0+0xf6/0x16b0 net/ipv6/addrconf.c:3738
 addrconf_notify+0xeb/0x1ba0 net/ipv6/addrconf.c:3662
 notifier_call_chain+0xb5/0x200 kernel/notifier.c:84
 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1938
 call_netdevice_notifiers_extack net/core/dev.c:1976 [inline]
 call_netdevice_notifiers net/core/dev.c:1990 [inline]
 netdev_wait_allrefs_any net/core/dev.c:10141 [inline]
 netdev_run_todo+0xb90/0x10b0 net/core/dev.c:10253
 tun_detach drivers/net/tun.c:696 [inline]
 tun_chr_close+0xe0/0x180 drivers/net/tun.c:3445
 __fput+0x277/0x9d0 fs/file_table.c:317
 task_work_run+0xdd/0x1a0 kernel/task_work.c:164
 exit_task_work include/linux/task_work.h:37 [inline]
 do_exit+0xaff/0x2a00 kernel/exit.c:795
 do_group_exit+0xd2/0x2f0 kernel/exit.c:925
 get_signal+0x22df/0x24c0 kernel/signal.c:2864
 arch_do_signal_or_restart+0x82/0x20f0 arch/x86/kernel/signal.c:867
 exit_to_user_mode_loop kernel/entry/common.c:166 [inline]
 exit_to_user_mode_prepare+0x15f/0x250 kernel/entry/common.c:201
 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
 syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:294
 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fec21cade11
Code: Unable to access opcode bytes at RIP 0x7fec21cadde7.
RSP: 002b:00007fec22d4d0b0 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6
RAX: fffffffffffffdfc RBX: 00007fec21d9bf60 RCX: 00007fec21cade11
RDX: 00007fec22d4d0f0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fec21ce308d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 00007fff4b45dd9f R14: 00007fec22d4d300 R15: 0000000000022000
 </TASK>

Allocated by task 3694:
 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:436 [inline]
 ____kasan_kmalloc mm/kasan/common.c:515 [inline]
 ____kasan_kmalloc mm/kasan/common.c:474 [inline]
 __kasan_kmalloc+0xa6/0xd0 mm/kasan/common.c:524
 kasan_kmalloc include/linux/kasan.h:234 [inline]
 kmem_cache_alloc_trace+0x1ea/0x4a0 mm/slab.c:3583
 kmalloc include/linux/slab.h:581 [inline]
 kzalloc include/linux/slab.h:714 [inline]
 fib6_net_init net/ipv6/ip6_fib.c:2376 [inline]
 fib6_net_init+0x1d7/0xa20 net/ipv6/ip6_fib.c:2351
 ops_init+0xaf/0x470 net/core/net_namespace.c:134
 setup_net+0x5d1/0xc50 net/core/net_namespace.c:325
 copy_net_ns+0x318/0x760 net/core/net_namespace.c:471
 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:226
 ksys_unshare+0x445/0x920 kernel/fork.c:3132
 __do_sys_unshare kernel/fork.c:3203 [inline]
 __se_sys_unshare kernel/fork.c:3201 [inline]
 __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3201
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Freed by task 3710:
 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
 kasan_set_track+0x21/0x30 mm/kasan/common.c:45
 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370
 ____kasan_slab_free mm/kasan/common.c:366 [inline]
 ____kasan_slab_free+0x13d/0x180 mm/kasan/common.c:328
 kasan_slab_free include/linux/kasan.h:200 [inline]
 __cache_free mm/slab.c:3439 [inline]
 kfree+0x113/0x310 mm/slab.c:3810
 fib6_net_exit+0x1c9/0x280 net/ipv6/ip6_fib.c:2438
 ops_exit_list+0xb0/0x170 net/core/net_namespace.c:162
 cleanup_net+0x4ea/0xb00 net/core/net_namespace.c:594
 process_one_work+0x996/0x1610 kernel/workqueue.c:2289
 worker_thread+0x665/0x1080 kernel/workqueue.c:2436
 kthread+0x2e9/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298

The buggy address belongs to the object at ffff888067149000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 0 bytes inside of
 2048-byte region [ffff888067149000, ffff888067149800)

The buggy address belongs to the physical page:
page:ffffea00019c5240 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x67149
flags: 0x4fff00000000200(slab|node=1|zone=1|lastcpupid=0x7ff)
raw: 04fff00000000200 ffffea00019d8008 ffffea00019c52c8 ffff888010c40800
raw: 0000000000000000 ffff888067149000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x40cc0(GFP_KERNEL|__GFP_COMP), pid 3694, tgid 3694 (syz-executor.3), ts 110210141508, free_ts 0
 prep_new_page mm/page_alloc.c:2441 [inline]
 get_page_from_freelist+0xba2/0x3e00 mm/page_alloc.c:4182
 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5408
 __alloc_pages_node include/linux/gfp.h:587 [inline]
 kmem_getpages mm/slab.c:1378 [inline]
 cache_grow_begin+0x75/0x350 mm/slab.c:2584
 fallback_alloc+0x1e4/0x2e0 mm/slab.c:3132
 __do_cache_alloc mm/slab.c:3274 [inline]
 slab_alloc mm/slab.c:3309 [inline]
 kmem_cache_alloc_trace+0x309/0x4a0 mm/slab.c:3581
 kmalloc include/linux/slab.h:581 [inline]
 kzalloc include/linux/slab.h:714 [inline]
 fib6_net_init net/ipv6/ip6_fib.c:2376 [inline]
 fib6_net_init+0x1d7/0xa20 net/ipv6/ip6_fib.c:2351
 ops_init+0xaf/0x470 net/core/net_namespace.c:134
 setup_net+0x5d1/0xc50 net/core/net_namespace.c:325
 copy_net_ns+0x318/0x760 net/core/net_namespace.c:471
 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:226
 ksys_unshare+0x445/0x920 kernel/fork.c:3132
 __do_sys_unshare kernel/fork.c:3203 [inline]
 __se_sys_unshare kernel/fork.c:3201 [inline]
 __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3201
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888067148f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888067148f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888067149000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff888067149080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888067149100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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