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BUG: KASAN: slab-use-after-free in xfrm_alloc_spi+0xf69/0x1220
Read of size 4 at addr ffff88800ba1f3c4 by task syz-executor.5/18058

CPU: 1 UID: 0 PID: 18058 Comm: syz-executor.5 Not tainted 6.16.0-rc5-next-20250711 #1 PREEMPT(voluntary) 
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xca/0x120
 print_report+0xcb/0x5f0
 kasan_report+0xca/0x100
 xfrm_alloc_spi+0xf69/0x1220
 xfrm_alloc_userspi+0x609/0xbb0
 xfrm_user_rcv_msg+0x459/0xa00
 netlink_rcv_skb+0x147/0x430
 xfrm_netlink_rcv+0x74/0x90
 netlink_unicast+0x58d/0x850
 netlink_sendmsg+0x8ac/0xd80
 ____sys_sendmsg+0xa67/0xc20
 ___sys_sendmsg+0x10f/0x1b0
 __sys_sendmsg+0x150/0x200
 do_syscall_64+0xbf/0x360
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe5eb1c2b19
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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe5e8738188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fe5eb2d5f60 RCX: 00007fe5eb1c2b19
RDX: 0000000000000000 RSI: 0000000020000400 RDI: 0000000000000003
RBP: 00007fe5eb21cf6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffcf9a18d9f R14: 00007fe5e8738300 R15: 0000000000022000
 </TASK>

Allocated by task 17936:
 kasan_save_stack+0x24/0x50
 kasan_save_track+0x14/0x30
 __kasan_slab_alloc+0x59/0x70
 kmem_cache_alloc_noprof+0x13c/0x470
 xfrm_state_alloc+0x25/0x600
 __find_acq_core+0x9c8/0x27a0
 xfrm_find_acq+0x7f/0xb0
 xfrm_alloc_userspi+0x58b/0xbb0
 xfrm_user_rcv_msg+0x459/0xa00
 netlink_rcv_skb+0x147/0x430
 xfrm_netlink_rcv+0x74/0x90
 netlink_unicast+0x58d/0x850
 netlink_sendmsg+0x8ac/0xd80
 ____sys_sendmsg+0xa67/0xc20
 ___sys_sendmsg+0x10f/0x1b0
 __sys_sendmsg+0x150/0x200
 do_syscall_64+0xbf/0x360
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 13913:
 kasan_save_stack+0x24/0x50
 kasan_save_track+0x14/0x30
 kasan_save_free_info+0x3a/0x60
 __kasan_slab_free+0x38/0x50
 kmem_cache_free+0x2a1/0x460
 xfrm_state_gc_task+0x112/0x170
 process_one_work+0x8e1/0x19c0
 worker_thread+0x67e/0xe90
 kthread+0x3c8/0x740
 ret_from_fork+0x34b/0x430
 ret_from_fork_asm+0x1a/0x30

The buggy address belongs to the object at ffff88800ba1f300
 which belongs to the cache xfrm_state of size 920
The buggy address is located 196 bytes inside of
 freed 920-byte region [ffff88800ba1f300, ffff88800ba1f698)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88800ba1ddc0 pfn:0xba1c
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x100000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0100000000000040 ffff88800a6f6000 dead000000000122 0000000000000000
raw: ffff88800ba1ddc0 00000000800f000b 00000000f5000000 0000000000000000
head: 0100000000000040 ffff88800a6f6000 dead000000000122 0000000000000000
head: ffff88800ba1ddc0 00000000800f000b 00000000f5000000 0000000000000000
head: 0100000000000002 ffffea00002e8701 00000000ffffffff 00000000ffffffff
head: 000000000000003d 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88800ba1f280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88800ba1f300: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88800ba1f380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff88800ba1f400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88800ba1f480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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