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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 ffff88801d8e7000 by task syz-executor.1/3640

CPU: 0 PID: 3640 Comm: syz-executor.1 Not tainted 5.19.0-rc3-syzkaller-00175-g0a18d802d65c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/18/2022
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/0x495 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:4894 [inline]
 rt6_disable_ip+0x7b7/0x9a0 net/ipv6/route.c:4899
 addrconf_ifdown.isra.0+0x11a/0x1830 net/ipv6/addrconf.c:3746
 addrconf_notify+0xeb/0x1ba0 net/ipv6/addrconf.c:3669
 notifier_call_chain+0xb5/0x200 kernel/notifier.c:87
 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1945
 call_netdevice_notifiers_extack net/core/dev.c:1983 [inline]
 call_netdevice_notifiers net/core/dev.c:1997 [inline]
 netdev_wait_allrefs_any net/core/dev.c:10227 [inline]
 netdev_run_todo+0xbc0/0x10f0 net/core/dev.c:10341
 tun_detach drivers/net/tun.c:703 [inline]
 tun_chr_close+0xe0/0x180 drivers/net/tun.c:3454
 __fput+0x277/0x9d0 fs/file_table.c:317
 task_work_run+0xdd/0x1a0 kernel/task_work.c:177
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0xaff/0x2a00 kernel/exit.c:795
 do_group_exit+0xd2/0x2f0 kernel/exit.c:925
 __do_sys_exit_group kernel/exit.c:936 [inline]
 __se_sys_exit_group kernel/exit.c:934 [inline]
 __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:934
 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+0x46/0xb0
RIP: 0033:0x7f462ee89109
Code: Unable to access opcode bytes at RIP 0x7f462ee890df.
RSP: 002b:00007ffc91f65f48 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007ffc91f660f0 RCX: 00007f462ee89109
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000043
RBP: 0000000000000000 R08: 0000000000000025 R09: 00007ffc91f660f0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f462eee302e
R13: 000000000000001c R14: 0000000000000004 R15: 00007ffc91f66130
 </TASK>

Allocated by task 3640:
 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+0xa9/0xd0 mm/kasan/common.c:524
 kmalloc include/linux/slab.h:600 [inline]
 kzalloc include/linux/slab.h:733 [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:3165
 __do_sys_unshare kernel/fork.c:3236 [inline]
 __se_sys_unshare kernel/fork.c:3234 [inline]
 __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3234
 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+0x46/0xb0

Freed by task 11:
 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+0x166/0x1a0 mm/kasan/common.c:328
 kasan_slab_free include/linux/kasan.h:200 [inline]
 slab_free_hook mm/slub.c:1754 [inline]
 slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1780
 slab_free mm/slub.c:3536 [inline]
 kfree+0xd6/0x4d0 mm/slub.c:4584
 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:302

The buggy address belongs to the object at ffff88801d8e7000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 0 bytes inside of
 2048-byte region [ffff88801d8e7000, ffff88801d8e7800)

The buggy address belongs to the physical page:
page:ffffea0000763800 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1d8e0
head:ffffea0000763800 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000001 ffff888011842000
raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 20, tgid 20 (cpuhp/1), ts 7462735461, free_ts 0
 prep_new_page mm/page_alloc.c:2456 [inline]
 get_page_from_freelist+0x1290/0x3b70 mm/page_alloc.c:4198
 __alloc_pages+0x1c7/0x510 mm/page_alloc.c:5426
 alloc_pages+0x1aa/0x310 mm/mempolicy.c:2272
 alloc_slab_page mm/slub.c:1824 [inline]
 allocate_slab+0x26c/0x3c0 mm/slub.c:1969
 new_slab mm/slub.c:2029 [inline]
 ___slab_alloc+0x9c4/0xe20 mm/slub.c:3031
 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3118
 slab_alloc_node mm/slub.c:3209 [inline]
 slab_alloc mm/slub.c:3251 [inline]
 kmem_cache_alloc_trace+0x310/0x3f0 mm/slub.c:3282
 kmalloc include/linux/slab.h:600 [inline]
 kzalloc include/linux/slab.h:733 [inline]
 __cpu_device_create drivers/base/cpu.c:414 [inline]
 cpu_device_create+0xd9/0x2c0 drivers/base/cpu.c:448
 cache_add_dev drivers/base/cacheinfo.c:632 [inline]
 cacheinfo_cpu_online drivers/base/cacheinfo.c:654 [inline]
 cacheinfo_cpu_online+0xae3/0x1af0 drivers/base/cacheinfo.c:648
 cpuhp_invoke_callback+0x662/0xe60 kernel/cpu.c:192
 cpuhp_thread_fun+0x477/0x6f0 kernel/cpu.c:785
 smpboot_thread_fn+0x645/0x9c0 kernel/smpboot.c:164
 kthread+0x2e9/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:302
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88801d8e6f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88801d8e6f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88801d8e7000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff88801d8e7080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801d8e7100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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