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BUG: KASAN: slab-out-of-bounds in fib6_drop_pcpu_from net/ipv6/ip6_fib.c:925 [inline]
BUG: KASAN: slab-out-of-bounds in fib6_purge_rt+0x1b3/0x5e0 net/ipv6/ip6_fib.c:937
Write of size 8 at addr ffff88809afffcfc by task kworker/u4:8/12445

CPU: 0 PID: 12445 Comm: kworker/u4:8 Not tainted 5.2.0-rc1+ #27
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:188
 __kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 kasan_report+0x12/0x20 mm/kasan/common.c:614
 check_memory_region_inline mm/kasan/generic.c:185 [inline]
 check_memory_region+0x123/0x190 mm/kasan/generic.c:191
 kasan_check_write+0x14/0x20 mm/kasan/common.c:100
 fib6_drop_pcpu_from net/ipv6/ip6_fib.c:925 [inline]
 fib6_purge_rt+0x1b3/0x5e0 net/ipv6/ip6_fib.c:937
 fib6_del_route net/ipv6/ip6_fib.c:1812 [inline]
 fib6_del+0xac2/0x10a0 net/ipv6/ip6_fib.c:1843
 fib6_clean_node+0x3a5/0x590 net/ipv6/ip6_fib.c:2005
 fib6_walk_continue+0x4a9/0x8e0 net/ipv6/ip6_fib.c:1927
 fib6_walk+0x9d/0x100 net/ipv6/ip6_fib.c:1975
 fib6_clean_tree+0xe0/0x120 net/ipv6/ip6_fib.c:2054
 __fib6_clean_all+0x118/0x2a0 net/ipv6/ip6_fib.c:2070
 fib6_clean_all+0x2b/0x40 net/ipv6/ip6_fib.c:2081
 rt6_sync_down_dev+0x134/0x150 net/ipv6/route.c:4169
 rt6_disable_ip+0x27/0x5f0 net/ipv6/route.c:4174
 addrconf_ifdown+0xa2/0x1220 net/ipv6/addrconf.c:3709
 addrconf_notify+0x5db/0x2270 net/ipv6/addrconf.c:3634
 notifier_call_chain+0xc2/0x230 kernel/notifier.c:95
 __raw_notifier_call_chain kernel/notifier.c:396 [inline]
 raw_notifier_call_chain+0x2e/0x40 kernel/notifier.c:403
 call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1753
 call_netdevice_notifiers_extack net/core/dev.c:1765 [inline]
 call_netdevice_notifiers net/core/dev.c:1779 [inline]
 dev_close_many+0x33f/0x6f0 net/core/dev.c:1522
 rollback_registered_many+0x43b/0xfc0 net/core/dev.c:8193
 unregister_netdevice_many.part.0+0x1b/0x1f0 net/core/dev.c:9324
 unregister_netdevice_many net/core/dev.c:9323 [inline]
 default_device_exit_batch+0x34e/0x410 net/core/dev.c:9793
 ops_exit_list.isra.0+0xfc/0x150 net/core/net_namespace.c:157
 cleanup_net+0x3fb/0x960 net/core/net_namespace.c:553
 process_one_work+0x989/0x1790 kernel/workqueue.c:2269
 worker_thread+0x98/0xe40 kernel/workqueue.c:2415
 kthread+0x354/0x420 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 13:
 save_stack+0x23/0x90 mm/kasan/common.c:71
 set_track mm/kasan/common.c:79 [inline]
 __kasan_kmalloc mm/kasan/common.c:489 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:462
 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:497
 slab_post_alloc_hook mm/slab.h:437 [inline]
 slab_alloc mm/slab.c:3326 [inline]
 kmem_cache_alloc+0x11a/0x6f0 mm/slab.c:3488
 kmem_cache_zalloc include/linux/slab.h:732 [inline]
 __kernfs_new_node+0xf0/0x6c0 fs/kernfs/dir.c:632
 kernfs_new_node+0x96/0x120 fs/kernfs/dir.c:698
 __kernfs_create_file+0x51/0x340 fs/kernfs/file.c:1002
 sysfs_add_file_mode_ns+0x222/0x560 fs/sysfs/file.c:305
 sysfs_create_file_ns+0x13d/0x1d0 fs/sysfs/file.c:331
 sysfs_create_file include/linux/sysfs.h:513 [inline]
 device_create_file+0xf6/0x1e0 drivers/base/core.c:1559
 device_add+0x5a3/0x17a0 drivers/base/core.c:2073
 device_register+0x1e/0x30 drivers/base/core.c:2184
 mce_device_create arch/x86/kernel/cpu/mce/core.c:2209 [inline]
 mce_cpu_online+0x39a/0x700 arch/x86/kernel/cpu/mce/core.c:2304
 cpuhp_invoke_callback+0x201/0x1af0 kernel/cpu.c:169
 cpuhp_thread_fun+0x496/0x8a0 kernel/cpu.c:686
 smpboot_thread_fn+0x6a3/0xa30 kernel/smpboot.c:165
 kthread+0x354/0x420 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff88809afffc40
 which belongs to the cache kernfs_node_cache of size 160
The buggy address is located 28 bytes to the right of
 160-byte region [ffff88809afffc40, ffff88809afffce0)
The buggy address belongs to the page:
page:ffffea00026bffc0 refcount:1 mapcount:0 mapping:ffff88821bc48500 index:0xffff88809affffee
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea00026bfb48 ffffea0002690008 ffff88821bc48500
raw: ffff88809affffee ffff88809afff000 0000000100000012 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809afffb80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88809afffc00: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
>ffff88809afffc80: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
                                                                ^
 ffff88809afffd00: fc fc fc fc 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88809afffd80: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
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