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BUG: KASAN: use-after-free in __xfrm_state_lookup+0x600/0x7d4 net/xfrm/xfrm_state.c:988
Read of size 2 at addr ffff0000f85c9922 by task syz.4.398/6074

CPU: 0 PID: 6074 Comm: syz.4.398 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026
Call trace:
 dump_backtrace+0x1c4/0x1f0 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106
 print_address_description+0x88/0x218 mm/kasan/report.c:316
 print_report+0x50/0x68 mm/kasan/report.c:420
 kasan_report+0xa8/0xfc mm/kasan/report.c:524
 __asan_report_load2_noabort+0x2c/0x38 mm/kasan/report_generic.c:349
 __xfrm_state_lookup+0x600/0x7d4 net/xfrm/xfrm_state.c:988
 __xfrm_state_locate net/xfrm/xfrm_state.c:1040 [inline]
 xfrm_state_add+0x1f8/0xa64 net/xfrm/xfrm_state.c:1497
 xfrm_add_sa+0x1d28/0x27b4 net/xfrm/xfrm_user.c:801
 xfrm_user_rcv_msg+0x500/0x7b8 net/xfrm/xfrm_user.c:3119
 netlink_rcv_skb+0x220/0x3ec net/netlink/af_netlink.c:2516
 xfrm_netlink_rcv+0x80/0x9c net/xfrm/xfrm_user.c:3141
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x5fc/0x80c net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x6f0/0x9d8 net/netlink/af_netlink.c:1877
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x588/0x90c net/socket.c:2519
 ___sys_sendmsg net/socket.c:2573 [inline]
 __sys_sendmsg+0x288/0x374 net/socket.c:2602
 __do_sys_sendmsg net/socket.c:2611 [inline]
 __se_sys_sendmsg net/socket.c:2609 [inline]
 __arm64_sys_sendmsg+0x80/0x94 net/socket.c:2609
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x12c arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:589

Allocated by task 4777:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4c/0x80 mm/kasan/common.c:53
 kasan_save_alloc_info+0x24/0x30 mm/kasan/generic.c:505
 __kasan_slab_alloc+0x70/0x88 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook+0x74/0x430 mm/slab.h:742
 slab_alloc_node mm/slub.c:3366 [inline]
 slab_alloc mm/slub.c:3374 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3381 [inline]
 kmem_cache_alloc+0x234/0x310 mm/slub.c:3390
 kmem_cache_zalloc include/linux/slab.h:689 [inline]
 xfrm_state_alloc+0x2c/0x23c net/xfrm/xfrm_state.c:648
 __find_acq_core+0x6d4/0x110c net/xfrm/xfrm_state.c:1432
 xfrm_find_acq+0x88/0xc0 net/xfrm/xfrm_state.c:1908
 xfrm_alloc_userspi+0x460/0x914 net/xfrm/xfrm_user.c:1598
 xfrm_user_rcv_msg+0x500/0x7b8 net/xfrm/xfrm_user.c:3119
 netlink_rcv_skb+0x220/0x3ec net/netlink/af_netlink.c:2516
 xfrm_netlink_rcv+0x80/0x9c net/xfrm/xfrm_user.c:3141
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x5fc/0x80c net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x6f0/0x9d8 net/netlink/af_netlink.c:1877
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x588/0x90c net/socket.c:2519
 ___sys_sendmsg net/socket.c:2573 [inline]
 __sys_sendmsg+0x288/0x374 net/socket.c:2602
 __do_sys_sendmsg net/socket.c:2611 [inline]
 __se_sys_sendmsg net/socket.c:2609 [inline]
 __arm64_sys_sendmsg+0x80/0x94 net/socket.c:2609
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x12c arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:589

Freed by task 14:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4c/0x80 mm/kasan/common.c:53
 kasan_save_free_info+0x38/0x5c mm/kasan/generic.c:516
 ____kasan_slab_free+0x148/0x1b0 mm/kasan/common.c:237
 __kasan_slab_free+0x18/0x28 mm/kasan/common.c:245
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1735 [inline]
 slab_free_freelist_hook+0x16c/0x1e8 mm/slub.c:1761
 slab_free mm/slub.c:3694 [inline]
 kmem_cache_free+0x118/0x318 mm/slub.c:3716
 xfrm_state_free net/xfrm/xfrm_state.c:507 [inline]
 xfrm_state_gc_destroy net/xfrm/xfrm_state.c:535 [inline]
 xfrm_state_gc_task+0x68c/0x88c net/xfrm/xfrm_state.c:551
 process_one_work+0x7e4/0x13bc kernel/workqueue.c:2292
 worker_thread+0x8cc/0xfe8 kernel/workqueue.c:2439
 kthread+0x254/0x2e0 kernel/kthread.c:376
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:854

The buggy address belongs to the object at ffff0000f85c9800
 which belongs to the cache xfrm_state of size 848
The buggy address is located 290 bytes inside of
 848-byte region [ffff0000f85c9800, ffff0000f85c9b50)

The buggy address belongs to the physical page:
page:00000000d9aab0a1 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff0000f85c8400 pfn:0x1385c8
head:00000000d9aab0a1 order:2 compound_mapcount:0 compound_pincount:0
flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000010200 0000000000000000 dead000000000001 ffff0000c0b81200
raw: ffff0000f85c8400 000000008010000a 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000f85c9800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff0000f85c9880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff0000f85c9900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff0000f85c9980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff0000f85c9a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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