==================================================================
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:560 [inline]
BUG: KASAN: slab-use-after-free in __xfrm_state_delete+0x696/0xca0 net/xfrm/xfrm_state.c:830
Write of size 8 at addr ffff88807df30030 by task syz.4.388/7409

CPU: 1 UID: 0 PID: 7409 Comm: syz.4.388 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <IRQ>
 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
 __hlist_del include/linux/list.h:982 [inline]
 hlist_del_rcu include/linux/rculist.h:560 [inline]
 __xfrm_state_delete+0x696/0xca0 net/xfrm/xfrm_state.c:830
 xfrm_timer_handler+0x18f/0xa00 net/xfrm/xfrm_state.c:716
 __run_hrtimer kernel/time/hrtimer.c:1761 [inline]
 __hrtimer_run_queues+0x52c/0xc60 kernel/time/hrtimer.c:1825
 hrtimer_run_softirq+0x187/0x2b0 kernel/time/hrtimer.c:1842
 handle_softirqs+0x283/0x870 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:dup_user_cpus_ptr+0x0/0x1d0 kernel/sched/core.c:2804
Code: 80 c1 03 38 c1 0f 8c f6 fe ff ff 48 89 df e8 f7 5f 93 00 e9 e9 fe ff ff 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <66> 0f 1f 00 55 41 57 41 56 41 55 41 54 53 50 41 89 d5 49 89 f6 49
RSP: 0018:ffffc9001c0a7948 EFLAGS: 00000246
RAX: 1ffff1100f836444 RBX: ffff88807c1b1e00 RCX: dffffc0000000000
RDX: 00000000ffffffff RSI: ffff8880783f3c00 RDI: ffff88807c1b1e00
RBP: 00000000ffffffff R08: ffffffff8fa3b537 R09: 1ffffffff1f476a6
R10: dffffc0000000000 R11: fffffbfff1f476a7 R12: ffff8880783f3c00
R13: ffff88807c1b1e00 R14: dffffc0000000000 R15: ffff88807c1b2220
 dup_task_struct+0x46a/0x860 kernel/fork.c:915
 copy_process+0x54b/0x3c00 kernel/fork.c:2004
 kernel_clone+0x21e/0x840 kernel/fork.c:2605
 __do_sys_clone3 kernel/fork.c:2909 [inline]
 __se_sys_clone3+0x256/0x2d0 kernel/fork.c:2888
 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: 0033:0x7fa1fadc3609
Code: d7 08 00 48 8d 3d 9c d7 08 00 e8 e2 28 f6 ff 66 90 b8 ea ff ff ff 48 85 ff 74 2c 48 85 d2 74 27 49 89 c8 b8 b3 01 00 00 0f 05 <48> 85 c0 7c 18 74 01 c3 31 ed 48 83 e4 f0 4c 89 c7 ff d2 48 89 c7
RSP: 002b:00007fff682a5608 EFLAGS: 00000206 ORIG_RAX: 00000000000001b3
RAX: ffffffffffffffda RBX: 00007fa1fad459f0 RCX: 00007fa1fadc3609
RDX: 00007fa1fad459f0 RSI: 0000000000000058 RDI: 00007fff682a5650
RBP: 00007fa1f8ff66c0 R08: 00007fa1f8ff66c0 R09: 00007fff682a5737
R10: 0000000000000008 R11: 0000000000000206 R12: ffffffffffffffa8
R13: 000000000000000b R14: 00007fff682a5650 R15: 00007fff682a5738
 </TASK>

Allocated by task 6102:
 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:330 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:356
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4191 [inline]
 slab_alloc_node mm/slub.c:4240 [inline]
 kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4247
 xfrm_state_alloc+0x24/0x2f0 net/xfrm/xfrm_state.c:733
 __find_acq_core+0x8a7/0x1c00 net/xfrm/xfrm_state.c:1833
 xfrm_find_acq+0x78/0xa0 net/xfrm/xfrm_state.c:2353
 xfrm_alloc_userspi+0x6b3/0xc90 net/xfrm/xfrm_user.c:1863
 xfrm_user_rcv_msg+0x7a3/0xab0 net/xfrm/xfrm_user.c:3501
 netlink_rcv_skb+0x208/0x470 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+0x82c/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 921:
 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:243 [inline]
 __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2422 [inline]
 slab_free mm/slub.c:4695 [inline]
 kmem_cache_free+0x18f/0x400 mm/slub.c:4797
 xfrm_state_free net/xfrm/xfrm_state.c:591 [inline]
 xfrm_state_gc_destroy net/xfrm/xfrm_state.c:618 [inline]
 xfrm_state_gc_task+0x52d/0x6b0 net/xfrm/xfrm_state.c:634
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x70e/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff88807df30000
 which belongs to the cache xfrm_state of size 928
The buggy address is located 48 bytes inside of
 freed 928-byte region [ffff88807df30000, ffff88807df303a0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88807df30000 pfn:0x7df30
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 ffff8881432f8c80 dead000000000122 0000000000000000
raw: ffff88807df30000 00000000800f000e 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff8881432f8c80 dead000000000122 0000000000000000
head: ffff88807df30000 00000000800f000e 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea0001f7cc01 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 6102, tgid 6098 (syz.0.31), ts 81637512590, free_ts 81612049983
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1851
 prep_new_page mm/page_alloc.c:1859 [inline]
 get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3858
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5148
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:2492 [inline]
 allocate_slab+0x8a/0x370 mm/slub.c:2660
 new_slab mm/slub.c:2714 [inline]
 ___slab_alloc+0xbeb/0x1420 mm/slub.c:3901
 __slab_alloc mm/slub.c:3992 [inline]
 __slab_alloc_node mm/slub.c:4067 [inline]
 slab_alloc_node mm/slub.c:4228 [inline]
 kmem_cache_alloc_noprof+0x283/0x3c0 mm/slub.c:4247
 xfrm_state_alloc+0x24/0x2f0 net/xfrm/xfrm_state.c:733
 __find_acq_core+0x8a7/0x1c00 net/xfrm/xfrm_state.c:1833
 xfrm_find_acq+0x78/0xa0 net/xfrm/xfrm_state.c:2353
 xfrm_alloc_userspi+0x6b3/0xc90 net/xfrm/xfrm_user.c:1863
 xfrm_user_rcv_msg+0x7a3/0xab0 net/xfrm/xfrm_user.c:3501
 netlink_rcv_skb+0x208/0x470 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+0x82c/0x9e0 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
page last free pid 6099 tgid 6091 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 __free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2895
 stack_depot_save_flags+0x436/0x860 lib/stackdepot.c:727
 kasan_save_stack mm/kasan/common.c:48 [inline]
 kasan_save_track+0x4f/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:388 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:405
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4407
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 ref_tracker_alloc+0x133/0x460 lib/ref_tracker.c:271
 __netdev_tracker_alloc include/linux/netdevice.h:4349 [inline]
 netdev_hold include/linux/netdevice.h:4378 [inline]
 dst_init+0xd9/0x450 net/core/dst.c:52
 dst_alloc+0x12a/0x170 net/core/dst.c:93
 rt_dst_alloc net/ipv4/route.c:1645 [inline]
 __mkroute_output net/ipv4/route.c:2649 [inline]
 ip_route_output_key_hash_rcu+0x1560/0x23e0 net/ipv4/route.c:2870
 ip_route_output_key_hash+0x1b9/0x2e0 net/ipv4/route.c:2700
 __ip_route_output_key include/net/route.h:169 [inline]
 ip_route_output_flow+0x2a/0x150 net/ipv4/route.c:2927
 ip_route_output_ports include/net/route.h:213 [inline]
 rxrpc_assess_MTU_size+0x3c7/0xa90 net/rxrpc/peer_object.c:173
 rxrpc_create_peer net/rxrpc/peer_object.c:297 [inline]
 rxrpc_lookup_peer+0x576/0xa60 net/rxrpc/peer_object.c:354
 rxrpc_new_client_call_for_sendmsg net/rxrpc/sendmsg.c:627 [inline]
 rxrpc_do_sendmsg+0xb0a/0x1220 net/rxrpc/sendmsg.c:695
 sock_sendmsg_nosec net/socket.c:714 [inline]
 __sock_sendmsg+0x219/0x270 net/socket.c:729
 ____sys_sendmsg+0x505/0x830 net/socket.c:2614

Memory state around the buggy address:
 ffff88807df2ff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88807df2ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88807df30000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff88807df30080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807df30100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
   0:	80 c1 03             	add    $0x3,%cl
   3:	38 c1                	cmp    %al,%cl
   5:	0f 8c f6 fe ff ff    	jl     0xffffff01
   b:	48 89 df             	mov    %rbx,%rdi
   e:	e8 f7 5f 93 00       	call   0x93600a
  13:	e9 e9 fe ff ff       	jmp    0xffffff01
  18:	66 90                	xchg   %ax,%ax
  1a:	90                   	nop
  1b:	90                   	nop
  1c:	90                   	nop
  1d:	90                   	nop
  1e:	90                   	nop
  1f:	90                   	nop
  20:	90                   	nop
  21:	90                   	nop
  22:	90                   	nop
  23:	90                   	nop
  24:	90                   	nop
  25:	90                   	nop
  26:	90                   	nop
  27:	90                   	nop
  28:	90                   	nop
  29:	90                   	nop
* 2a:	66 0f 1f 00          	nopw   (%rax) <-- trapping instruction
  2e:	55                   	push   %rbp
  2f:	41 57                	push   %r15
  31:	41 56                	push   %r14
  33:	41 55                	push   %r13
  35:	41 54                	push   %r12
  37:	53                   	push   %rbx
  38:	50                   	push   %rax
  39:	41 89 d5             	mov    %edx,%r13d
  3c:	49 89 f6             	mov    %rsi,%r14
  3f:	49                   	rex.WB