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BUG: KASAN: slab-use-after-free in __hlist_del include/linux/list.h:980 [inline]
BUG: KASAN: slab-use-after-free in hlist_del_rcu include/linux/rculist.h:513 [inline]
BUG: KASAN: slab-use-after-free in __xfrm_state_delete+0x454/0x800 net/xfrm/xfrm_state.c:753
Write of size 8 at addr ffff888026b19428 by task kworker/u4:14/5926

CPU: 1 PID: 5926 Comm: kworker/u4:14 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 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
 __hlist_del include/linux/list.h:980 [inline]
 hlist_del_rcu include/linux/rculist.h:513 [inline]
 __xfrm_state_delete+0x454/0x800 net/xfrm/xfrm_state.c:753
 xfrm_state_delete net/xfrm/xfrm_state.c:776 [inline]
 xfrm_state_delete_tunnel+0x9e/0x1e0 net/xfrm/xfrm_state.c:2805
 ipcomp_destroy+0x4a/0x80 net/xfrm/xfrm_ipcomp.c:318
 ___xfrm_state_destroy+0x1fd/0x4d0 net/xfrm/xfrm_state.c:539
 __xfrm_state_destroy net/xfrm/xfrm_state.c:729 [inline]
 xfrm_state_put_sync include/net/xfrm.h:828 [inline]
 xfrm_state_flush+0x50e/0x830 net/xfrm/xfrm_state.c:863
 xfrm6_tunnel_net_exit+0x46/0x100 net/ipv6/xfrm6_tunnel.c:338
 ops_exit_list net/core/net_namespace.c:173 [inline]
 cleanup_net+0x6f4/0xb90 net/core/net_namespace.c:652
 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 12694:
 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 ffff888026b19400
 which belongs to the cache xfrm_state of size 848
The buggy address is located 40 bytes inside of
 freed 848-byte region [ffff888026b19400, ffff888026b19750)

The buggy address belongs to the physical page:
page:ffffea00009ac600 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888026b19400 pfn:0x26b18
head:ffffea00009ac600 order:2 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff88801d6c6280 0000000000000000 0000000000000001
raw: ffff888026b19400 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 10460, tgid 10445 (syz.7.1129), ts 666163006145, free_ts 666152903082
 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
 ipcomp6_tunnel_create net/ipv6/ipcomp6.c:79 [inline]
 ipcomp6_tunnel_attach net/ipv6/ipcomp6.c:124 [inline]
 ipcomp6_init_state+0x2bd/0x7f0 net/ipv6/ipcomp6.c:161
 __xfrm_init_state+0xd8b/0x11c0 net/xfrm/xfrm_state.c:2904
 xfrm_init_state+0x1f/0x80 net/xfrm/xfrm_state.c:2932
 pfkey_msg2xfrm_state net/key/af_key.c:1286 [inline]
 pfkey_add+0x1cee/0x2da0 net/key/af_key.c:1503
 pfkey_process net/key/af_key.c:2847 [inline]
 pfkey_sendmsg+0xbed/0x1050 net/key/af_key.c:3698
 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
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
 free_large_kmalloc+0x101/0x1a0 mm/slab_common.c:984
 bpf_check+0x62c6/0xe970 kernel/bpf/verifier.c:20555
 bpf_prog_load+0x11cb/0x16d0 kernel/bpf/syscall.c:2750
 __sys_bpf+0x55a/0x800 kernel/bpf/syscall.c:5473
 __do_sys_bpf kernel/bpf/syscall.c:5577 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5575 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5575
 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

Memory state around the buggy address:
 ffff888026b19300: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
 ffff888026b19380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888026b19400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                  ^
 ffff888026b19480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888026b19500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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