==================================================================
BUG: KASAN: slab-out-of-bounds in xfrm_policy_inexact_list_reinsert+0x606/0x6c0 net/xfrm/xfrm_policy.c:853
Read of size 1 at addr ffff88811decd3f8 by task syz.3.304/1242

CPU: 0 PID: 1242 Comm: syz.3.304 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:88
 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:427 [inline]
 kasan_report+0xf1/0x140 mm/kasan/report.c:444
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report_generic.c:306
 xfrm_policy_inexact_list_reinsert+0x606/0x6c0 net/xfrm/xfrm_policy.c:853
 xfrm_policy_inexact_node_merge net/xfrm/xfrm_policy.c:985 [inline]
 xfrm_policy_inexact_insert_node+0x938/0xb50 net/xfrm/xfrm_policy.c:1041
 xfrm_policy_inexact_alloc_chain+0x53d/0xb30 net/xfrm/xfrm_policy.c:1157
 xfrm_policy_inexact_insert+0x70/0x1130 net/xfrm/xfrm_policy.c:1200
 xfrm_policy_insert+0x126/0x9a0 net/xfrm/xfrm_policy.c:1586
 xfrm_add_policy+0x4ed/0x850 net/xfrm/xfrm_user.c:1832
 xfrm_user_rcv_msg+0x4dc/0x7b0 net/xfrm/xfrm_user.c:2981
 netlink_rcv_skb+0x1f5/0x440 net/netlink/af_netlink.c:2511
 xfrm_netlink_rcv+0x72/0x90 net/xfrm/xfrm_user.c:3003
 netlink_unicast_kernel net/netlink/af_netlink.c:1322 [inline]
 netlink_unicast+0x876/0xa40 net/netlink/af_netlink.c:1348
 netlink_sendmsg+0x879/0xb80 net/netlink/af_netlink.c:1922
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 ____sys_sendmsg+0x5b7/0x8f0 net/socket.c:2435
 ___sys_sendmsg+0x236/0x2e0 net/socket.c:2489
 __sys_sendmsg net/socket.c:2518 [inline]
 __do_sys_sendmsg net/socket.c:2527 [inline]
 __se_sys_sendmsg net/socket.c:2525 [inline]
 __x64_sys_sendmsg+0x206/0x2f0 net/socket.c:2525
 x64_sys_call+0x4b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f1fee469799
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:00007f1fecec4028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f1fee6e2fa0 RCX: 00007f1fee469799
RDX: 0000000000000000 RSI: 0000200000000580 RDI: 0000000000000006
RBP: 00007f1fee4ffc99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1fee6e3038 R14: 00007f1fee6e2fa0 R15: 00007ffe5ca74d78
 </TASK>

Allocated by task 1242:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:433 [inline]
 ____kasan_kmalloc mm/kasan/common.c:512 [inline]
 __kasan_kmalloc+0xda/0x110 mm/kasan/common.c:521
 kasan_kmalloc include/linux/kasan.h:227 [inline]
 __kmalloc+0x13d/0x2c0 mm/slub.c:4436
 kmalloc include/linux/slab.h:624 [inline]
 sk_prot_alloc+0xed/0x320 net/core/sock.c:1868
 sk_alloc+0x38/0x430 net/core/sock.c:1928
 pfkey_create+0x12a/0x660 net/key/af_key.c:152
 __sock_create+0x38d/0x7a0 net/socket.c:1485
 sock_create net/socket.c:1541 [inline]
 __sys_socket+0xec/0x190 net/socket.c:1583
 __do_sys_socket net/socket.c:1592 [inline]
 __se_sys_socket net/socket.c:1590 [inline]
 __x64_sys_socket+0x7a/0x90 net/socket.c:1590
 x64_sys_call+0x8c5/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:42
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

The buggy address belongs to the object at ffff88811decd000
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 1016 bytes inside of
 1024-byte region [ffff88811decd000, ffff88811decd400)
The buggy address belongs to the page:
page:ffffea000477b200 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11dec8
head:ffffea000477b200 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head|zone=1)
raw: 4000000000010200 ffffea000473dc00 0000000200000002 ffff888100043080
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 139, ts 17477034223, free_ts 17112723114
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x192/0x1b0 mm/page_alloc.c:2605
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2611
 get_page_from_freelist+0x2d3a/0x2dc0 mm/page_alloc.c:4485
 __alloc_pages+0x1a2/0x460 mm/page_alloc.c:5822
 alloc_slab_page mm/slub.c:-1 [inline]
 allocate_slab mm/slub.c:1937 [inline]
 new_slab+0xa1/0x4d0 mm/slub.c:2000
 ___slab_alloc+0x381/0x810 mm/slub.c:3033
 __slab_alloc+0x49/0x90 mm/slub.c:3120
 slab_alloc_node mm/slub.c:3211 [inline]
 slab_alloc mm/slub.c:3255 [inline]
 __kmalloc_track_caller+0x169/0x2c0 mm/slub.c:4954
 kmalloc_reserve net/core/skbuff.c:357 [inline]
 __alloc_skb+0x21a/0x740 net/core/skbuff.c:428
 alloc_skb include/linux/skbuff.h:1183 [inline]
 alloc_skb_with_frags+0xa8/0x620 net/core/skbuff.c:6194
 sock_alloc_send_pskb+0x87f/0x9a0 net/core/sock.c:2542
 unix_dgram_sendmsg+0x5f7/0x1890 net/unix/af_unix.c:1816
 unix_seqpacket_sendmsg+0x118/0x1e0 net/unix/af_unix.c:2277
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 sock_write_iter+0x2a6/0x3a0 net/socket.c:1079
 do_iter_readv_writev+0x478/0x5f0 fs/read_write.c:-1
 do_iter_write+0x1fa/0x7b0 fs/read_write.c:855
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1472 [inline]
 free_pcp_prepare mm/page_alloc.c:1544 [inline]
 free_unref_page_prepare+0x542/0x550 mm/page_alloc.c:3534
 free_unref_page+0xae/0x540 mm/page_alloc.c:3616
 free_the_page mm/page_alloc.c:805 [inline]
 __free_pages+0x6c/0x100 mm/page_alloc.c:5898
 free_nonslab_page+0x86/0xc0 mm/slub.c:3564
 kfree+0x19a/0x270 mm/slub.c:4585
 skb_free_head net/core/skbuff.c:656 [inline]
 skb_release_data+0x814/0xa10 net/core/skbuff.c:678
 skb_release_all net/core/skbuff.c:743 [inline]
 __kfree_skb net/core/skbuff.c:757 [inline]
 consume_skb+0xab/0x1f0 net/core/skbuff.c:930
 skb_free_datagram+0x28/0xe0 net/core/datagram.c:325
 netlink_recvmsg+0x5c6/0xe10 net/netlink/af_netlink.c:2001
 ____sys_recvmsg+0x2cd/0x5e0 net/socket.c:-1
 ___sys_recvmsg+0x21a/0x5c0 net/socket.c:2696
 __sys_recvmsg net/socket.c:2726 [inline]
 __do_sys_recvmsg net/socket.c:2736 [inline]
 __se_sys_recvmsg net/socket.c:2733 [inline]
 __x64_sys_recvmsg+0x203/0x2f0 net/socket.c:2733
 x64_sys_call+0x705/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:48
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Memory state around the buggy address:
 ffff88811decd280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88811decd300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88811decd380: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
                                                                ^
 ffff88811decd400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88811decd480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================