==================================================================
BUG: KASAN: slab-use-after-free in __hlist_del include/linux/list.h:982 [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+0x47c/0x800 net/xfrm/xfrm_state.c:753
Write of size 8 at addr ffff888023475430 by task syz-executor/30539

CPU: 0 PID: 30539 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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
 __hlist_del include/linux/list.h:982 [inline]
 hlist_del_rcu include/linux/rculist.h:513 [inline]
 __xfrm_state_delete+0x47c/0x800 net/xfrm/xfrm_state.c:753
 xfrm_timer_handler+0x1c3/0x9e0 net/xfrm/xfrm_state.c:644
 __run_hrtimer kernel/time/hrtimer.c:1755 [inline]
 __hrtimer_run_queues+0x51e/0xc40 kernel/time/hrtimer.c:1819
 hrtimer_run_softirq+0x187/0x2b0 kernel/time/hrtimer.c:1836
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:__preempt_count_add arch/x86/include/asm/preempt.h:80 [inline]
RIP: 0010:rcu_is_watching+0x6/0xb0 kernel/rcu/tree.c:699
Code: eb 99 e8 4d 80 fe 08 48 c7 c7 80 6c d3 8c 4c 89 f6 e8 1e fd e1 02 e9 53 ff ff ff 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 41 57 <41> 56 53 65 ff 05 98 21 94 7e e8 2b 96 fe 08 89 c3 83 f8 08 73 60
RSP: 0018:ffffc9000bc774a8 EFLAGS: 00000202
RAX: ffffffff81e797d2 RBX: ffffffff81e797a2 RCX: 0000000000000000
RDX: ffff88802cfe0000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: dffffc0000000000 R09: 1ffffffff21b4ea0
R10: dffffc0000000000 R11: fffffbfff21b4ea1 R12: ffffea0001529c00
R13: dffffc0000000000 R14: ffffea0001529c00 R15: 0000000001529c00
 rcu_read_lock include/linux/rcupdate.h:787 [inline]
 page_ext_get+0x5b/0x2b0 mm/page_ext.c:508
 page_table_check_set+0x51/0x6f0 mm/page_table_check.c:114
 page_table_check_ptes_set include/linux/page_table_check.h:74 [inline]
 set_ptes include/linux/pgtable.h:238 [inline]
 copy_present_pte mm/memory.c:978 [inline]
 copy_pte_range mm/memory.c:1082 [inline]
 copy_pmd_range mm/memory.c:1167 [inline]
 copy_pud_range mm/memory.c:1204 [inline]
 copy_p4d_range mm/memory.c:1228 [inline]
 copy_page_range+0x248d/0x3600 mm/memory.c:1322
 dup_mmap kernel/fork.c:764 [inline]
 dup_mm kernel/fork.c:1692 [inline]
 copy_mm+0x112a/0x1c20 kernel/fork.c:1741
 copy_process+0x16d3/0x3d70 kernel/fork.c:2506
 kernel_clone+0x21b/0x840 kernel/fork.c:2914
 __do_sys_clone kernel/fork.c:3057 [inline]
 __se_sys_clone kernel/fork.c:3041 [inline]
 __x64_sys_clone+0x18c/0x1e0 kernel/fork.c:3041
 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
RIP: 0033:0x7fb454385493
Code: 1f 84 00 00 00 00 00 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 89 c2 85 c0 75 2c 64 48 8b 04 25 10 00 00
RSP: 002b:00007ffecb617aa8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb454385493
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001
R10: 00005555937d47d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00000000000927c0 R14: 000000000016eb53 R15: 00007ffecb617c40
 </TASK>

Allocated by task 2098:
 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

Freed by task 965:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
 kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522
 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236
 kasan_slab_free include/linux/kasan.h:164 [inline]
 slab_free_hook mm/slub.c:1811 [inline]
 slab_free_freelist_hook+0x130/0x1b0 mm/slub.c:1837
 slab_free mm/slub.c:3830 [inline]
 kmem_cache_free+0xf8/0x280 mm/slub.c:3852
 xfrm_state_gc_task+0x10a/0x160 net/xfrm/xfrm_state.c:562
 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

The buggy address belongs to the object at ffff888023475400
 which belongs to the cache xfrm_state of size 848
The buggy address is located 48 bytes inside of
 freed 848-byte region [ffff888023475400, ffff888023475750)

The buggy address belongs to the physical page:
page:ffffea00008d1d00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x23474
head:ffffea00008d1d00 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 ffff88814168d000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000080100010 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 11698, tgid 11697 (syz.3.2404), ts 446058380390, free_ts 446035445333
 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_add_acquire+0x105/0xaf0 net/xfrm/xfrm_user.c:2722
 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_save_free_info+0x2e/0x50 mm/kasan/generic.c:522
 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236
 kasan_slab_free include/linux/kasan.h:164 [inline]
 slab_free_hook mm/slub.c:1811 [inline]
 slab_free_freelist_hook+0x130/0x1b0 mm/slub.c:1837
 slab_free mm/slub.c:3830 [inline]
 kmem_cache_free+0xf8/0x280 mm/slub.c:3852
 nlmon_xmit+0xb0/0x100 drivers/net/nlmon.c:15
 __netdev_start_xmit include/linux/netdevice.h:4943 [inline]
 netdev_start_xmit include/linux/netdevice.h:4957 [inline]
 xmit_one net/core/dev.c:3619 [inline]
 dev_hard_start_xmit+0x246/0x740 net/core/dev.c:3635
 __dev_queue_xmit+0x1a64/0x35a0 net/core/dev.c:4425
 dev_queue_xmit include/linux/netdevice.h:3113 [inline]
 __netlink_deliver_tap_skb net/netlink/af_netlink.c:307 [inline]
 __netlink_deliver_tap+0x5ab/0x830 net/netlink/af_netlink.c:325
 netlink_deliver_tap+0x19c/0x1b0 net/netlink/af_netlink.c:338
 netlink_deliver_tap_kernel net/netlink/af_netlink.c:347 [inline]
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x72c/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

Memory state around the buggy address:
 ffff888023475300: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
 ffff888023475380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888023475400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff888023475480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888023475500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
   0:	eb 99                	jmp    0xffffff9b
   2:	e8 4d 80 fe 08       	call   0x8fe8054
   7:	48 c7 c7 80 6c d3 8c 	mov    $0xffffffff8cd36c80,%rdi
   e:	4c 89 f6             	mov    %r14,%rsi
  11:	e8 1e fd e1 02       	call   0x2e1fd34
  16:	e9 53 ff ff ff       	jmp    0xffffff6e
  1b:	66 0f 1f 84 00 00 00 	nopw   0x0(%rax,%rax,1)
  22:	00 00
  24:	f3 0f 1e fa          	endbr64
  28:	41 57                	push   %r15
* 2a:	41 56                	push   %r14 <-- trapping instruction
  2c:	53                   	push   %rbx
  2d:	65 ff 05 98 21 94 7e 	incl   %gs:0x7e942198(%rip)        # 0x7e9421cc
  34:	e8 2b 96 fe 08       	call   0x8fe9664
  39:	89 c3                	mov    %eax,%ebx
  3b:	83 f8 08             	cmp    $0x8,%eax
  3e:	73 60                	jae    0xa0