==================================================================
BUG: KASAN: slab-use-after-free in __xfrm_state_lookup+0x6b2/0x8d0 net/xfrm/xfrm_state.c:1084
Read of size 2 at addr ffff88801df68922 by task kworker/u4:3/48

CPU: 0 PID: 48 Comm: kworker/u4:3 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: ipv6_addrconf addrconf_dad_work
Call Trace:
 <IRQ>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xac/0x220 mm/kasan/report.c:468
 kasan_report+0x117/0x150 mm/kasan/report.c:581
 __xfrm_state_lookup+0x6b2/0x8d0 net/xfrm/xfrm_state.c:1084
 xfrm_state_lookup+0xef/0x1a0 net/xfrm/xfrm_state.c:2042
 xfrm_input+0x3d62/0x6a20 net/xfrm/xfrm_input.c:575
 tunnel64_rcv+0xd7/0x2c0 net/ipv4/tunnel4.c:149
 ip_protocol_deliver_rcu+0x20e/0x3f0 net/ipv4/ip_input.c:205
 ip_local_deliver_finish+0x2ca/0x510 net/ipv4/ip_input.c:233
 NF_HOOK+0x303/0x390 include/linux/netfilter.h:304
 NF_HOOK+0x303/0x390 include/linux/netfilter.h:304
 __netif_receive_skb_one_core net/core/dev.c:5608 [inline]
 __netif_receive_skb+0xcc/0x290 net/core/dev.c:5722
 process_backlog+0x380/0x6e0 net/core/dev.c:6050
 __napi_poll+0xc0/0x460 net/core/dev.c:6612
 napi_poll net/core/dev.c:6679 [inline]
 net_rx_action+0x5ea/0xbf0 net/core/dev.c:6815
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 do_softirq+0xed/0x180 kernel/softirq.c:479
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x178/0x1c0 kernel/softirq.c:406
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:856 [inline]
 __dev_queue_xmit+0x1449/0x35a0 net/core/dev.c:4452
 neigh_output include/net/neighbour.h:543 [inline]
 ip6_finish_output2+0xe2e/0x1650 net/ipv6/ip6_output.c:141
 dst_output include/net/dst.h:467 [inline]
 NF_HOOK+0x163/0x470 include/linux/netfilter.h:304
 mld_sendpack+0x7f9/0xd70 net/ipv6/mcast.c:1823
 ipv6_mc_dad_complete+0x88/0x210 net/ipv6/mcast.c:2248
 addrconf_dad_completed+0x6d0/0xd40 net/ipv6/addrconf.c:4304
 addrconf_dad_work+0xc4e/0x14e0 net/ipv6/addrconf.c:-1
 process_one_work kernel/workqueue.c:2634 [inline]
 process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>

Allocated by task 10806:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:328
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook+0x6e/0x4d0 mm/slab.h:767
 slab_alloc_node mm/slub.c:3495 [inline]
 slab_alloc mm/slub.c:3503 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3510 [inline]
 kmem_cache_alloc+0x11e/0x2e0 mm/slub.c:3519
 kmem_cache_zalloc include/linux/slab.h:711 [inline]
 xfrm_state_alloc+0x22/0x2a0 net/xfrm/xfrm_state.c:661
 __find_acq_core+0x7d8/0x19d0 net/xfrm/xfrm_state.c:1598
 xfrm_find_acq+0x6a/0x90 net/xfrm/xfrm_state.c:2070
 xfrm_alloc_userspi+0x57a/0xa90 net/xfrm/xfrm_user.c:1613
 xfrm_user_rcv_msg+0x596/0x870 net/xfrm/xfrm_user.c:3169
 netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2545
 xfrm_netlink_rcv+0x79/0x90 net/xfrm/xfrm_user.c:3191
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x751/0x8d0 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0x5bf/0x950 net/socket.c:2595
 ___sys_sendmsg+0x220/0x290 net/socket.c:2649
 __sys_sendmsg net/socket.c:2678 [inline]
 __do_sys_sendmsg net/socket.c:2687 [inline]
 __se_sys_sendmsg+0x1a5/0x270 net/socket.c:2685
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

The buggy address belongs to the object at ffff88801df68800
 which belongs to the cache xfrm_state of size 848
The buggy address is located 290 bytes inside of
 freed 848-byte region [ffff88801df68800, ffff88801df68b50)

The buggy address belongs to the physical page:
page:ffffea000077da00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88801df68400 pfn:0x1df68
head:ffffea000077da00 order:2 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff8881406fc3c0 dead000000000122 0000000000000000
raw: ffff88801df68400 000000008010000d 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x152820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_HARDWALL), pid 9502, tgid 9499 (syz.0.1385), ts 261624763765, free_ts 260813297265
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1cd/0x210 mm/page_alloc.c:1554
 prep_new_page mm/page_alloc.c:1561 [inline]
 get_page_from_freelist+0x195c/0x19f0 mm/page_alloc.c:3191
 __alloc_pages+0x1e3/0x460 mm/page_alloc.c:4457
 alloc_slab_page+0x5d/0x170 mm/slub.c:1881
 allocate_slab mm/slub.c:2028 [inline]
 new_slab+0x87/0x2e0 mm/slub.c:2081
 ___slab_alloc+0xc6d/0x1300 mm/slub.c:3253
 __slab_alloc mm/slub.c:3339 [inline]
 __slab_alloc_node mm/slub.c:3392 [inline]
 slab_alloc_node mm/slub.c:3485 [inline]
 slab_alloc mm/slub.c:3503 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3510 [inline]
 kmem_cache_alloc+0x1b7/0x2e0 mm/slub.c:3519
 kmem_cache_zalloc include/linux/slab.h:711 [inline]
 xfrm_state_alloc+0x22/0x2a0 net/xfrm/xfrm_state.c:661
 xfrm_state_construct net/xfrm/xfrm_user.c:689 [inline]
 xfrm_add_sa+0xfe5/0x30a0 net/xfrm/xfrm_user.c:799
 xfrm_user_rcv_msg+0x596/0x870 net/xfrm/xfrm_user.c:3169
 netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2545
 xfrm_netlink_rcv+0x79/0x90 net/xfrm/xfrm_user.c:3191
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x751/0x8d0 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0x5bf/0x950 net/socket.c:2595
 ___sys_sendmsg+0x220/0x290 net/socket.c:2649
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1154 [inline]
 free_unref_page_prepare+0x7ce/0x8e0 mm/page_alloc.c:2336
 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2429
 __stack_depot_save+0x572/0x630 lib/stackdepot.c:443
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x5f/0x70 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:374 [inline]
 __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:383
 kasan_kmalloc include/linux/kasan.h:198 [inline]
 __do_kmalloc_node mm/slab_common.c:1007 [inline]
 __kmalloc_node+0xb4/0x230 mm/slab_common.c:1014
 kmalloc_node include/linux/slab.h:620 [inline]
 kzalloc_node include/linux/slab.h:732 [inline]
 crypto_alloc_tfmmem crypto/api.c:496 [inline]
 crypto_create_tfm_node+0x7b/0x3b0 crypto/api.c:516
 crypto_create_tfm crypto/internal.h:137 [inline]
 crypto_spawn_tfm2+0x5c/0x90 crypto/algapi.c:835
 crypto_spawn_ahash include/crypto/internal/hash.h:223 [inline]
 crypto_authenc_init_tfm+0x48/0x220 crypto/authenc.c:315
 crypto_create_tfm_node+0x15c/0x3b0 crypto/api.c:522
 crypto_alloc_tfm_node+0x176/0x330 crypto/api.c:623
 esp_init_authenc net/ipv4/esp4.c:1042 [inline]
 esp_init_state+0x5a7/0x11b0 net/ipv4/esp4.c:1112
 __xfrm_init_state+0xd8b/0x11c0 net/xfrm/xfrm_state.c:2904
 xfrm_state_construct net/xfrm/xfrm_user.c:741 [inline]
 xfrm_add_sa+0x236d/0x30a0 net/xfrm/xfrm_user.c:799
 xfrm_user_rcv_msg+0x596/0x870 net/xfrm/xfrm_user.c:3169
 netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2545

Memory state around the buggy address:
 ffff88801df68800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801df68880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88801df68900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff88801df68980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801df68a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================