veth0_vlan: left promiscuous mode
veth1_macvtap: left promiscuous mode
veth0_macvtap: left promiscuous mode
veth1_vlan: left promiscuous mode
veth0_vlan: left promiscuous mode
==================================================================
BUG: KASAN: slab-use-after-free in __hlist_del include/linux/list.h:994 [inline]
BUG: KASAN: slab-use-after-free in detach_timer+0x12e/0x300 kernel/time/timer.c:891
Write of size 8 at addr ffff8880560f5f40 by task kworker/u8:13/4346

CPU: 0 UID: 0 PID: 4346 Comm: kworker/u8:13 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xba/0x230 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 __hlist_del include/linux/list.h:994 [inline]
 detach_timer+0x12e/0x300 kernel/time/timer.c:891
 detach_if_pending kernel/time/timer.c:910 [inline]
 __timer_delete kernel/time/timer.c:1381 [inline]
 timer_delete+0x2ee/0x340 kernel/time/timer.c:1406
 addrconf_del_rs_timer net/ipv6/addrconf.c:318 [inline]
 addrconf_ifdown+0x6e4/0x1aa0 net/ipv6/addrconf.c:3917
 addrconf_notify+0x1bc/0x1050 net/ipv6/addrconf.c:-1
 notifier_call_chain+0x1be/0x400 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline]
 call_netdevice_notifiers net/core/dev.c:2301 [inline]
 netif_close_many+0x2ae/0x420 net/core/dev.c:1804
 unregister_netdevice_many_notify+0xb47/0x2360 net/core/dev.c:12373
 unregister_netdevice_many net/core/dev.c:12466 [inline]
 default_device_exit_batch+0x981/0xa00 net/core/dev.c:13058
 ops_exit_list net/core/net_namespace.c:205 [inline]
 ops_undo_list+0x52b/0x940 net/core/net_namespace.c:252
 cleanup_net+0x56e/0x800 net/core/net_namespace.c:704
 process_one_work kernel/workqueue.c:3275 [inline]
 process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 4346:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 unpoison_slab_object mm/kasan/common.c:340 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4501 [inline]
 slab_alloc_node mm/slub.c:4830 [inline]
 kmem_cache_alloc_node_noprof+0x22a/0x6e0 mm/slub.c:4882
 kmalloc_reserve net/core/skbuff.c:613 [inline]
 __alloc_skb+0x27d/0x7d0 net/core/skbuff.c:713
 alloc_skb include/linux/skbuff.h:1383 [inline]
 nlmsg_new include/net/netlink.h:1055 [inline]
 inet6_rt_notify+0x170/0x470 net/ipv6/route.c:6355
 fib6_del_route net/ipv6/ip6_fib.c:2057 [inline]
 fib6_del+0x10af/0x15a0 net/ipv6/ip6_fib.c:2092
 fib6_clean_node+0x29c/0x580 net/ipv6/ip6_fib.c:2254
 fib6_walk_continue+0x67b/0x910 net/ipv6/ip6_fib.c:2176
 fib6_walk net/ipv6/ip6_fib.c:2224 [inline]
 fib6_clean_tree net/ipv6/ip6_fib.c:2304 [inline]
 __fib6_clean_all+0x3aa/0x610 net/ipv6/ip6_fib.c:2320
 rt6_sync_down_dev net/ipv6/route.c:5013 [inline]
 rt6_disable_ip+0x11f/0x750 net/ipv6/route.c:5018
 addrconf_ifdown+0x157/0x1aa0 net/ipv6/addrconf.c:3858
 addrconf_notify+0x1bc/0x1050 net/ipv6/addrconf.c:-1
 notifier_call_chain+0x1be/0x400 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline]
 call_netdevice_notifiers net/core/dev.c:2301 [inline]
 netif_close_many+0x2ae/0x420 net/core/dev.c:1804
 unregister_netdevice_many_notify+0xb47/0x2360 net/core/dev.c:12373
 unregister_netdevice_many net/core/dev.c:12466 [inline]
 default_device_exit_batch+0x981/0xa00 net/core/dev.c:13058
 ops_exit_list net/core/net_namespace.c:205 [inline]
 ops_undo_list+0x52b/0x940 net/core/net_namespace.c:252
 cleanup_net+0x56e/0x800 net/core/net_namespace.c:704
 process_one_work kernel/workqueue.c:3275 [inline]
 process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 4346:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2687 [inline]
 slab_free mm/slub.c:6124 [inline]
 kmem_cache_free+0x185/0x6b0 mm/slub.c:6254
 skb_kfree_head net/core/skbuff.c:1087 [inline]
 skb_free_head net/core/skbuff.c:1101 [inline]
 skb_release_data+0x6c3/0x940 net/core/skbuff.c:1128
 skb_release_all net/core/skbuff.c:1203 [inline]
 __kfree_skb+0x5d/0x210 net/core/skbuff.c:1217
 netlink_broadcast_filtered+0xede/0x1010 net/netlink/af_netlink.c:1535
 nlmsg_multicast_filtered include/net/netlink.h:1165 [inline]
 nlmsg_multicast include/net/netlink.h:1184 [inline]
 nlmsg_notify+0xf0/0x1a0 net/netlink/af_netlink.c:2593
 fib6_del_route net/ipv6/ip6_fib.c:2057 [inline]
 fib6_del+0x10af/0x15a0 net/ipv6/ip6_fib.c:2092
 fib6_clean_node+0x29c/0x580 net/ipv6/ip6_fib.c:2254
 fib6_walk_continue+0x67b/0x910 net/ipv6/ip6_fib.c:2176
 fib6_walk net/ipv6/ip6_fib.c:2224 [inline]
 fib6_clean_tree net/ipv6/ip6_fib.c:2304 [inline]
 __fib6_clean_all+0x3aa/0x610 net/ipv6/ip6_fib.c:2320
 rt6_sync_down_dev net/ipv6/route.c:5013 [inline]
 rt6_disable_ip+0x11f/0x750 net/ipv6/route.c:5018
 addrconf_ifdown+0x157/0x1aa0 net/ipv6/addrconf.c:3858
 addrconf_notify+0x1bc/0x1050 net/ipv6/addrconf.c:-1
 notifier_call_chain+0x1be/0x400 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline]
 call_netdevice_notifiers net/core/dev.c:2301 [inline]
 netif_close_many+0x2ae/0x420 net/core/dev.c:1804
 unregister_netdevice_many_notify+0xb47/0x2360 net/core/dev.c:12373
 unregister_netdevice_many net/core/dev.c:12466 [inline]
 default_device_exit_batch+0x981/0xa00 net/core/dev.c:13058
 ops_exit_list net/core/net_namespace.c:205 [inline]
 ops_undo_list+0x52b/0x940 net/core/net_namespace.c:252
 cleanup_net+0x56e/0x800 net/core/net_namespace.c:704
 process_one_work kernel/workqueue.c:3275 [inline]
 process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff8880560f5d40
 which belongs to the cache skbuff_small_head of size 704
The buggy address is located 512 bytes inside of
 freed 704-byte region [ffff8880560f5d40, ffff8880560f6000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x560f4
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff88814044ac80 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000130013 00000000f5000000 0000000000000000
head: 0080000000000040 ffff88814044ac80 dead000000000100 dead000000000122
head: 0000000000000000 0000000000130013 00000000f5000000 0000000000000000
head: 0080000000000002 ffffea0001583d01 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4346, tgid 4346 (kworker/u8:13), ts 304281042047, free_ts 300764109826
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x28bb/0x2950 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
 alloc_slab_page mm/slub.c:3255 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3444
 new_slab mm/slub.c:3502 [inline]
 refill_objects+0x334/0x3c0 mm/slub.c:7134
 refill_sheaf mm/slub.c:2804 [inline]
 __pcs_replace_empty_main+0x328/0x5f0 mm/slub.c:4578
 alloc_from_pcs mm/slub.c:4681 [inline]
 slab_alloc_node mm/slub.c:4815 [inline]
 kmem_cache_alloc_node_noprof+0x4f4/0x6e0 mm/slub.c:4882
 kmalloc_reserve net/core/skbuff.c:613 [inline]
 __alloc_skb+0x27d/0x7d0 net/core/skbuff.c:713
 alloc_skb include/linux/skbuff.h:1383 [inline]
 nlmsg_new include/net/netlink.h:1055 [inline]
 inet_ifmcaddr_notify+0x7e/0x150 net/ipv4/igmp.c:1481
 __ip_mc_dec_group+0x414/0x620 net/ipv4/igmp.c:1778
 inetdev_event+0x2b1/0x1610 net/ipv4/devinet.c:1641
 notifier_call_chain+0x1be/0x400 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline]
 call_netdevice_notifiers net/core/dev.c:2301 [inline]
 netif_close_many+0x2ae/0x420 net/core/dev.c:1804
 unregister_netdevice_many_notify+0xb47/0x2360 net/core/dev.c:12373
 unregister_netdevice_many net/core/dev.c:12466 [inline]
 default_device_exit_batch+0x981/0xa00 net/core/dev.c:13058
 ops_exit_list net/core/net_namespace.c:205 [inline]
 ops_undo_list+0x52b/0x940 net/core/net_namespace.c:252
page last free pid 4346 tgid 4346 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0xfe3/0x1170 mm/page_alloc.c:2978
 device_release+0x9e/0x1d0 drivers/base/core.c:-1
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x228/0x560 lib/kobject.c:737
 netdev_run_todo+0xc75/0xde0 net/core/dev.c:11720
 ieee80211_unregister_hw+0x128/0x2c0 net/mac80211/main.c:1701
 mac80211_hwsim_del_radio+0x28a/0x490 drivers/net/wireless/virtual/mac80211_hwsim.c:5916
 hwsim_exit_net+0xf02/0xfc0 drivers/net/wireless/virtual/mac80211_hwsim.c:6807
 ops_exit_list net/core/net_namespace.c:199 [inline]
 ops_undo_list+0x49f/0x940 net/core/net_namespace.c:252
 cleanup_net+0x56e/0x800 net/core/net_namespace.c:704
 process_one_work kernel/workqueue.c:3275 [inline]
 process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff8880560f5e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880560f5e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880560f5f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff8880560f5f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880560f6000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================