KASAN: use-after-free Write in __xfrm_state

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KASAN: slab-use-after-free Write in __xfrm_state_delete net	22	syz, C	done		4863	377d	460d	29/29	fixed on 2025/10/29 21:02
linux-6.6	KASAN: slab-use-after-free Write in __xfrm_state_delete origin:lts-only	22	syz		inconclusive	10	401d	429d	0/2	upstream: reported syz repro on 2025/08/29 09:56

================================================================== BUG: KASAN: use-after-free in __hlist_del include/linux/list.h:906 [inline] BUG: KASAN: use-after-free in hlist_del_init_rcu include/linux/rculist.h:184 [inline] BUG: KASAN: use-after-free in __xfrm_state_delete+0x3db/0x940 net/xfrm/xfrm_state.c:700 Write of size 8 at addr ffff88802a5c6218 by task syz.2.1460/10217 CPU: 0 PID: 10217 Comm: syz.2.1460 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026 Call Trace: <IRQ> dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 print_address_description mm/kasan/report.c:316 [inline] print_report+0xa8/0x210 mm/kasan/report.c:420 kasan_report+0x10b/0x140 mm/kasan/report.c:524 __hlist_del include/linux/list.h:906 [inline] hlist_del_init_rcu include/linux/rculist.h:184 [inline] __xfrm_state_delete+0x3db/0x940 net/xfrm/xfrm_state.c:700 xfrm_timer_handler+0x10b/0x970 net/xfrm/xfrm_state.c:631 __run_hrtimer kernel/time/hrtimer.c:1751 [inline] __hrtimer_run_queues+0x522/0xc90 kernel/time/hrtimer.c:1815 hrtimer_run_softirq+0x173/0x290 kernel/time/hrtimer.c:1832 handle_softirqs+0x291/0x910 kernel/softirq.c:596 __do_softirq kernel/softirq.c:630 [inline] invoke_softirq kernel/softirq.c:470 [inline] __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118 </IRQ> <TASK> asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0xbc/0x120 kernel/locking/spinlock.c:194 Code: c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 41 c6 04 07 f8 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 9f 64 17 f7 65 8b 05 30 01 c1 75 85 c0 74 3c 48 c7 04 24 0e 36 RSP: 0018:ffffc9000d33f5c0 EFLAGS: 00000206 RAX: dffffc0000000004 RBX: 0000000000000a06 RCX: 112c6ec06f6e1700 RDX: dffffc0000000000 RSI: ffffffff8aac1cc0 RDI: 0000000000000001 RBP: ffffc9000d33f650 R08: ffffffff91b622ef R09: 1ffffffff236c45d R10: dffffc0000000000 R11: fffffbfff236c45e R12: dffffc0000000000 R13: 0000000000000000 R14: ffff88807c3016c0 R15: 1ffff92001a67eb8 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] __wake_up_common_lock kernel/sched/wait.c:140 [inline] __wake_up_sync_key+0x128/0x190 kernel/sched/wait.c:208 __unix_dgram_recvmsg+0x4b7/0xda0 net/unix/af_unix.c:2490 ____sys_recvmsg+0x2c8/0x5b0 net/socket.c:-1 ___sys_recvmsg+0x210/0x590 net/socket.c:2780 do_recvmmsg+0x370/0x810 net/socket.c:2874 __sys_recvmmsg net/socket.c:2953 [inline] __do_sys_recvmmsg net/socket.c:2976 [inline] __se_sys_recvmmsg net/socket.c:2969 [inline] __x64_sys_recvmmsg+0x195/0x250 net/socket.c:2969 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fe89eb9f559 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fe89fa37028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007fe89ee26090 RCX: 00007fe89eb9f559 RDX: 0000000000010106 RSI: 0000200000000280 RDI: 0000000000000003 RBP: 00007fe89ec36b50 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe89ee26128 R14: 00007fe89ee26090 R15: 00007ffc9fcf8cb8 </TASK> Allocated by task 4289: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 ____kasan_kmalloc mm/kasan/common.c:375 [inline] __kasan_kmalloc+0x8e/0xa0 mm/kasan/common.c:384 kasan_kmalloc include/linux/kasan.h:211 [inline] __do_kmalloc_node mm/slab_common.c:936 [inline] __kmalloc+0xb3/0x240 mm/slab_common.c:949 xfrm_state_init+0x125/0x470 net/xfrm/xfrm_state.c:2796 xfrm_net_init+0x1a3/0xeb0 net/xfrm/xfrm_policy.c:4186 ops_init+0x360/0x5e0 net/core/net_namespace.c:138 setup_net+0x4f2/0xbd0 net/core/net_namespace.c:336 copy_net_ns+0x33e/0x5b0 net/core/net_namespace.c:508 create_new_namespaces+0x3ce/0x700 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0x116/0x160 kernel/nsproxy.c:226 ksys_unshare+0x4f6/0x8e0 kernel/fork.c:3289 __do_sys_unshare kernel/fork.c:3363 [inline] __se_sys_unshare kernel/fork.c:3361 [inline] __x64_sys_unshare+0x34/0x40 kernel/fork.c:3361 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Freed by task 4449: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x27/0x40 mm/kasan/generic.c:516 ____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1735 [inline] slab_free_freelist_hook+0x133/0x1b0 mm/slub.c:1761 slab_free mm/slub.c:3694 [inline] __kmem_cache_free+0xb6/0x200 mm/slub.c:3707 xfrm_hash_resize+0xdce/0xff0 net/xfrm/xfrm_state.c:198 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 The buggy address belongs to the object at ffff88802a5c6200 which belongs to the cache kmalloc-64 of size 64 The buggy address is located 24 bytes inside of 64-byte region [ffff88802a5c6200, ffff88802a5c6240) The buggy address belongs to the physical page: page:ffffea0000a97180 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2a5c6 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffffea000091a840 dead000000000002 ffff888018441640 raw: 0000000000000000 0000000000200020 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 1, tgid 1 (swapper/0), ts 17153038823, free_ts 0 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2560 prep_new_page mm/page_alloc.c:2567 [inline] get_page_from_freelist+0x206b/0x2180 mm/page_alloc.c:4358 __alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5658 alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2117 alloc_slab_page+0x5d/0x180 mm/slub.c:1805 allocate_slab mm/slub.c:1950 [inline] new_slab+0x87/0x2d0 mm/slub.c:2003 ___slab_alloc+0xbc5/0x1240 mm/slub.c:3161 __slab_alloc mm/slub.c:3247 [inline] slab_alloc_node mm/slub.c:3332 [inline] __kmem_cache_alloc_node+0x126/0x270 mm/slub.c:3405 __do_kmalloc_node mm/slab_common.c:935 [inline] __kmalloc+0xa3/0x240 mm/slab_common.c:949 kmalloc include/linux/slab.h:568 [inline] kzalloc include/linux/slab.h:699 [inline] kobject_get_path+0xac/0x220 lib/kobject.c:152 kobject_uevent_env+0x28d/0x890 lib/kobject_uevent.c:544 device_add+0xac2/0x1050 drivers/base/core.c:3679 usb_new_device+0xa01/0x15e0 drivers/usb/core/hub.c:2669 register_root_hub+0x258/0x550 drivers/usb/core/hcd.c:1021 usb_add_hcd+0xbb9/0x1080 drivers/usb/core/hcd.c:3001 vhci_hcd_probe+0x140/0x370 drivers/usb/usbip/vhci_hcd.c:1387 page_owner free stack trace missing Memory state around the buggy address: ffff88802a5c6100: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff88802a5c6180: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >ffff88802a5c6200: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ^ ffff88802a5c6280: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff88802a5c6300: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ================================================================== ---------------- Code disassembly (best guess): 0: c7 44 24 20 00 00 00 movl $0x0,0x20(%rsp) 7: 00 8: 9c pushf 9: 8f 44 24 20 pop 0x20(%rsp) d: f7 44 24 20 00 02 00 testl $0x200,0x20(%rsp) 14: 00 15: 41 c6 04 07 f8 movb $0xf8,(%r15,%rax,1) 1a: 75 4b jne 0x67 1c: f7 c3 00 02 00 00 test $0x200,%ebx 22: 74 01 je 0x25 24: fb sti 25: bf 01 00 00 00 mov $0x1,%edi * 2a: e8 9f 64 17 f7 call 0xf71764ce <-- trapping instruction 2f: 65 8b 05 30 01 c1 75 mov %gs:0x75c10130(%rip),%eax # 0x75c10166 36: 85 c0 test %eax,%eax 38: 74 3c je 0x76 3a: 48 rex.W 3b: c7 .byte 0xc7 3c: 04 24 add $0x24,%al 3e: 0e (bad) 3f: 36 ss

Crashes (3):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Assets (help?)	Manager	Title
2026/11/01 12:59	linux-6.1.y	08889840163e	25a0ae84	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci2-linux-6-1-kasan	KASAN: use-after-free Write in __xfrm_state_delete
2026/10/31 04:30	linux-6.1.y	08889840163e	0ec395f8	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci2-linux-6-1-kasan	KASAN: use-after-free Write in __xfrm_state_delete
2026/10/30 21:58	linux-6.1.y	08889840163e	0ec395f8	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci2-linux-6-1-kasan-arm64	KASAN: use-after-free Write in __xfrm_state_delete

Crashes (3):

Assets (help?)