==================================================================
BUG: KASAN: slab-use-after-free in __xfrm_state_insert+0x8af/0x1450 net/xfrm/xfrm_state.c:1743
Read of size 1 at addr ffff88805687c330 by task syz.4.1405/10899

CPU: 0 UID: 0 PID: 10899 Comm: syz.4.1405 Not tainted 6.16.0-syzkaller-06620-gae633388cae3 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 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
 __xfrm_state_insert+0x8af/0x1450 net/xfrm/xfrm_state.c:1743
 xfrm_state_insert+0x54/0x60 net/xfrm/xfrm_state.c:1795
 ipcomp6_tunnel_attach net/ipv6/ipcomp6.c:131 [inline]
 ipcomp6_init_state+0x655/0x900 net/ipv6/ipcomp6.c:163
 __xfrm_init_state+0xa73/0x13f0 net/xfrm/xfrm_state.c:3188
 xfrm_init_state+0x18/0xa0 net/xfrm/xfrm_state.c:3231
 pfkey_msg2xfrm_state net/key/af_key.c:1286 [inline]
 pfkey_add+0x1d38/0x2e00 net/key/af_key.c:1504
 pfkey_process net/key/af_key.c:2848 [inline]
 pfkey_sendmsg+0xbfb/0x1090 net/key/af_key.c:3699
 sock_sendmsg_nosec net/socket.c:714 [inline]
 __sock_sendmsg+0x219/0x270 net/socket.c:729
 ____sys_sendmsg+0x52d/0x830 net/socket.c:2614
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2668
 __sys_sendmmsg+0x227/0x430 net/socket.c:2757
 __do_sys_sendmmsg net/socket.c:2784 [inline]
 __se_sys_sendmmsg net/socket.c:2781 [inline]
 __x64_sys_sendmmsg+0xa0/0xc0 net/socket.c:2781
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2f0638ebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f2f071fb038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f2f065b5fa0 RCX: 00007f2f0638ebe9
RDX: 000000000400008a RSI: 0000200000000180 RDI: 0000000000000006
RBP: 00007f2f06411e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2f065b6038 R14: 00007f2f065b5fa0 R15: 00007fff55325ef8
 </TASK>

Allocated by task 9571:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:319 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:345
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4148 [inline]
 slab_alloc_node mm/slub.c:4197 [inline]
 kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4204
 xfrm_state_alloc+0x24/0x2f0 net/xfrm/xfrm_state.c:733
 xfrm_add_acquire+0xf7/0xb20 net/xfrm/xfrm_user.c:2990
 xfrm_user_rcv_msg+0x7a3/0xab0 net/xfrm/xfrm_user.c:3501
 netlink_rcv_skb+0x205/0x470 net/netlink/af_netlink.c:2552
 xfrm_netlink_rcv+0x79/0x90 net/xfrm/xfrm_user.c:3523
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:714 [inline]
 __sock_sendmsg+0x219/0x270 net/socket.c:729
 ____sys_sendmsg+0x505/0x830 net/socket.c:2614
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2668
 __sys_sendmsg net/socket.c:2700 [inline]
 __do_sys_sendmsg net/socket.c:2705 [inline]
 __se_sys_sendmsg net/socket.c:2703 [inline]
 __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2703
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 9571:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2381 [inline]
 slab_free mm/slub.c:4643 [inline]
 kmem_cache_free+0x18f/0x400 mm/slub.c:4745
 xfrm_add_acquire+0x9cc/0xb20 net/xfrm/xfrm_user.c:3037
 xfrm_user_rcv_msg+0x7a3/0xab0 net/xfrm/xfrm_user.c:3501
 netlink_rcv_skb+0x205/0x470 net/netlink/af_netlink.c:2552
 xfrm_netlink_rcv+0x79/0x90 net/xfrm/xfrm_user.c:3523
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:714 [inline]
 __sock_sendmsg+0x219/0x270 net/socket.c:729
 ____sys_sendmsg+0x505/0x830 net/socket.c:2614
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2668
 __sys_sendmsg net/socket.c:2700 [inline]
 __do_sys_sendmsg net/socket.c:2705 [inline]
 __se_sys_sendmsg net/socket.c:2703 [inline]
 __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2703
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88805687c000
 which belongs to the cache xfrm_state of size 928
The buggy address is located 816 bytes inside of
 freed 928-byte region [ffff88805687c000, ffff88805687c3a0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88805687f300 pfn:0x5687c
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 ffff888022aafa00 dead000000000122 0000000000000000
raw: ffff88805687f300 00000000800f0004 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff888022aafa00 dead000000000122 0000000000000000
head: ffff88805687f300 00000000800f0004 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea00015a1f01 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 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5994, tgid 5993 (syz.2.3), ts 89706375205, free_ts 89704005094
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1704
 prep_new_page mm/page_alloc.c:1712 [inline]
 get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3669
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4959
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2419
 alloc_slab_page mm/slub.c:2451 [inline]
 allocate_slab+0x8a/0x3b0 mm/slub.c:2619
 new_slab mm/slub.c:2673 [inline]
 ___slab_alloc+0xbfc/0x1480 mm/slub.c:3859
 __slab_alloc mm/slub.c:3949 [inline]
 __slab_alloc_node mm/slub.c:4024 [inline]
 slab_alloc_node mm/slub.c:4185 [inline]
 kmem_cache_alloc_noprof+0x283/0x3c0 mm/slub.c:4204
 xfrm_state_alloc+0x24/0x2f0 net/xfrm/xfrm_state.c:733
 pfkey_msg2xfrm_state net/key/af_key.c:1122 [inline]
 pfkey_add+0x6e4/0x2e00 net/key/af_key.c:1504
 pfkey_process net/key/af_key.c:2848 [inline]
 pfkey_sendmsg+0xbfb/0x1090 net/key/af_key.c:3699
 sock_sendmsg_nosec net/socket.c:714 [inline]
 __sock_sendmsg+0x219/0x270 net/socket.c:729
 ____sys_sendmsg+0x505/0x830 net/socket.c:2614
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2668
 __sys_sendmsg net/socket.c:2700 [inline]
 __do_sys_sendmsg net/socket.c:2705 [inline]
 __se_sys_sendmsg net/socket.c:2703 [inline]
 __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2703
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5991 tgid 5984 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1248 [inline]
 __free_frozen_pages+0xc71/0xe70 mm/page_alloc.c:2706
 stack_depot_save_flags+0x445/0x900 lib/stackdepot.c:678
 ref_tracker_free+0xfe/0x7d0 lib/ref_tracker.c:308
 __netns_tracker_free include/net/net_namespace.h:374 [inline]
 put_net_track include/net/net_namespace.h:389 [inline]
 __sk_destruct+0x3c3/0x660 net/core/sock.c:2368
 l2cap_sock_release+0x158/0x1d0 net/bluetooth/l2cap_sock.c:1435
 __sock_release net/socket.c:649 [inline]
 sock_close+0xc0/0x240 net/socket.c:1439
 __fput+0x449/0xa70 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+0x6b5/0x22e0 kernel/exit.c:964
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1105
 get_signal+0x1286/0x1340 kernel/signal.c:3034
 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:208 [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]
 ret_from_fork+0x47f/0x770 arch/x86/kernel/process.c:157
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff88805687c200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805687c280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88805687c300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff88805687c380: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88805687c400: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
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