syzbot

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BUG: KASAN: slab-use-after-free in ip6_rcv_core+0x1304/0x1590 net/ipv6/ip6_input.c:199
Read of size 1 at addr ffff88806325ad90 by task kworker/0:10/9046

CPU: 0 UID: 0 PID: 9046 Comm: kworker/0:10 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: wg-crypt-wg0 wg_packet_tx_worker
Call Trace:
 <IRQ>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 ip6_rcv_core+0x1304/0x1590 net/ipv6/ip6_input.c:199
 ipv6_rcv+0x72/0xc0 net/ipv6/ip6_input.c:308
 __netif_receive_skb_one_core net/core/dev.c:6079 [inline]
 __netif_receive_skb+0xd3/0x380 net/core/dev.c:6192
 process_backlog+0x60e/0x14f0 net/core/dev.c:6544
 __napi_poll+0xc7/0x360 net/core/dev.c:7594
 napi_poll net/core/dev.c:7657 [inline]
 net_rx_action+0x5f7/0xdf0 net/core/dev.c:7784
 handle_softirqs+0x286/0x870 kernel/softirq.c:622
 do_softirq+0xec/0x180 kernel/softirq.c:523
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x17d/0x1c0 kernel/softirq.c:450
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:936 [inline]
 keep_key_fresh drivers/net/wireguard/send.c:135 [inline]
 wg_packet_create_data_done drivers/net/wireguard/send.c:259 [inline]
 wg_packet_tx_worker+0x586/0x7c0 drivers/net/wireguard/send.c:276
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 1681:
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 unpoison_slab_object mm/kasan/common.c:342 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:368
 kasan_slab_alloc include/linux/kasan.h:252 [inline]
 slab_post_alloc_hook mm/slub.c:4978 [inline]
 slab_alloc_node mm/slub.c:5288 [inline]
 kmem_cache_alloc_node_noprof+0x433/0x710 mm/slub.c:5340
 kmalloc_reserve+0xbd/0x290 net/core/skbuff.c:579
 __alloc_skb+0x142/0x2d0 net/core/skbuff.c:670
 alloc_skb include/linux/skbuff.h:1383 [inline]
 ndisc_alloc_skb+0x9f/0x480 net/ipv6/ndisc.c:420
 ndisc_send_rs+0x2b5/0x630 net/ipv6/ndisc.c:706
 addrconf_rs_timer+0x369/0x670 net/ipv6/addrconf.c:4037
 call_timer_fn+0x17e/0x5f0 kernel/time/timer.c:1747
 expire_timers kernel/time/timer.c:1798 [inline]
 __run_timers kernel/time/timer.c:2372 [inline]
 __run_timer_base+0x61a/0x860 kernel/time/timer.c:2384
 run_timer_base kernel/time/timer.c:2393 [inline]
 run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2403
 handle_softirqs+0x286/0x870 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:723
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697

Freed by task 9046:
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 __kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587
 kasan_save_free_info mm/kasan/kasan.h:406 [inline]
 poison_slab_object mm/kasan/common.c:252 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284
 kasan_slab_free include/linux/kasan.h:234 [inline]
 slab_free_hook mm/slub.c:2543 [inline]
 slab_free mm/slub.c:6642 [inline]
 kmem_cache_free+0x19b/0x690 mm/slub.c:6752
 pskb_expand_head+0x382/0x1150 net/core/skbuff.c:2273
 netif_skb_check_for_xdp net/core/dev.c:5439 [inline]
 netif_receive_generic_xdp net/core/dev.c:5470 [inline]
 do_xdp_generic+0x8c5/0x11a0 net/core/dev.c:5538
 __netif_receive_skb_core+0x18f4/0x4380 net/core/dev.c:5889
 __netif_receive_skb_one_core net/core/dev.c:6077 [inline]
 __netif_receive_skb+0x72/0x380 net/core/dev.c:6192
 netif_receive_skb_internal net/core/dev.c:6278 [inline]
 netif_receive_skb+0x1cb/0x790 net/core/dev.c:6337
 NF_HOOK+0xa0/0x390 include/linux/netfilter.h:319
 br_handle_frame_finish+0x15c6/0x1c90 net/bridge/br_input.c:235
 br_nf_hook_thresh+0x3c6/0x4a0 net/bridge/br_netfilter_hooks.c:-1
 br_nf_pre_routing_finish_ipv6+0x999/0xd60 net/bridge/br_netfilter_ipv6.c:-1
 NF_HOOK include/linux/netfilter.h:318 [inline]
 br_nf_pre_routing_ipv6+0x37e/0x6b0 net/bridge/br_netfilter_ipv6.c:184
 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:291 [inline]
 br_handle_frame+0x96e/0x14f0 net/bridge/br_input.c:442
 __netif_receive_skb_core+0x10b9/0x4380 net/core/dev.c:5966
 __netif_receive_skb_one_core net/core/dev.c:6077 [inline]
 __netif_receive_skb+0x72/0x380 net/core/dev.c:6192
 process_backlog+0x60e/0x14f0 net/core/dev.c:6544
 __napi_poll+0xc7/0x360 net/core/dev.c:7594
 napi_poll net/core/dev.c:7657 [inline]
 net_rx_action+0x5f7/0xdf0 net/core/dev.c:7784
 handle_softirqs+0x286/0x870 kernel/softirq.c:622
 do_softirq+0xec/0x180 kernel/softirq.c:523
 __local_bh_enable_ip+0x17d/0x1c0 kernel/softirq.c:450
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:936 [inline]
 keep_key_fresh drivers/net/wireguard/send.c:135 [inline]
 wg_packet_create_data_done drivers/net/wireguard/send.c:259 [inline]
 wg_packet_tx_worker+0x586/0x7c0 drivers/net/wireguard/send.c:276
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 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 ffff88806325ad80
 which belongs to the cache skbuff_small_head of size 704
The buggy address is located 16 bytes inside of
 freed 704-byte region [ffff88806325ad80, ffff88806325b040)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x63258
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff888140e9cb40 ffffea00012afe00 dead000000000002
raw: 0000000000000000 0000000000130013 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff888140e9cb40 ffffea00012afe00 dead000000000002
head: 0000000000000000 0000000000130013 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea00018c9601 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 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 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5829, tgid 5829 (syz-executor), ts 391959524923, free_ts 391859251871
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x234/0x290 mm/page_alloc.c:1845
 prep_new_page mm/page_alloc.c:1853 [inline]
 get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3879
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5178
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:3059 [inline]
 allocate_slab+0x96/0x350 mm/slub.c:3232
 new_slab mm/slub.c:3286 [inline]
 ___slab_alloc+0xf56/0x1990 mm/slub.c:4655
 __slab_alloc+0x65/0x100 mm/slub.c:4778
 __slab_alloc_node mm/slub.c:4854 [inline]
 slab_alloc_node mm/slub.c:5276 [inline]
 kmem_cache_alloc_node_noprof+0x4c5/0x710 mm/slub.c:5340
 kmalloc_reserve+0xbd/0x290 net/core/skbuff.c:579
 __alloc_skb+0x142/0x2d0 net/core/skbuff.c:670
 skb_copy+0x188/0x800 net/core/skbuff.c:2125
 mac80211_hwsim_tx_frame_no_nl+0xcd3/0x11c0 drivers/net/wireless/virtual/mac80211_hwsim.c:1891
 mac80211_hwsim_tx_frame+0x1b5/0x200 drivers/net/wireless/virtual/mac80211_hwsim.c:2264
 mac80211_hwsim_beacon_tx+0x3f0/0x860 drivers/net/wireless/virtual/mac80211_hwsim.c:2365
 __iterate_interfaces+0x2ab/0x590 net/mac80211/util.c:761
 ieee80211_iterate_active_interfaces_atomic+0xdb/0x180 net/mac80211/util.c:797
page last free pid 15606 tgid 15599 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1394 [inline]
 __free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2901
 free_large_kmalloc+0x13a/0x1f0 mm/slub.c:6775
 device_release+0x9c/0x1c0 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+0x22b/0x480 lib/kobject.c:737
 netdev_run_todo+0xd2e/0xea0 net/core/dev.c:11601
 tun_detach drivers/net/tun.c:640 [inline]
 tun_chr_close+0x13c/0x1c0 drivers/net/tun.c:3436
 __fput+0x44c/0xa70 fs/file_table.c:468
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x6b5/0x2300 kernel/exit.c:966
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1107
 get_signal+0x1285/0x1340 kernel/signal.c:3034
 arch_do_signal_or_restart+0xa0/0x790 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x72/0x130 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88806325ac80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88806325ad00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88806325ad80: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff88806325ae00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88806325ae80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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