[syzbot] [net?] kernel BUG in pfkey_send_migrate

[syzbot <syzbot+b518dfc8e021988fbd55@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    99600f79b28c mpls: add missing unregister_netdevice_notifi..
git tree:       net
console output: https://syzkaller.appspot.com/x/log.txt?x=12291def980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=779072223d02a312
dashboard link: https://syzkaller.appspot.com/bug?extid=b518dfc8e021988fbd55
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15123c16580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1598434a580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c7ebefcbe2a3/disk-99600f79.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/02ff03abfaec/vmlinux-99600f79.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0c74709d060b/bzImage-99600f79.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b518dfc8e021988fbd55@syzkaller.appspotmail.com

skbuff: skb_over_panic: text:ffffffff8a752120 len:392 put:16 head:ffff88802a4ad040 data:ffff88802a4ad040 tail:0x188 end:0x180 dev:<NULL>
------------[ cut here ]------------
kernel BUG at net/core/skbuff.c:214!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 5984 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:skb_panic+0x157/0x160 net/core/skbuff.c:214
Code: c7 60 24 dc 8c 48 8b 74 24 08 48 8b 54 24 10 8b 0c 24 44 8b 44 24 04 4d 89 e9 50 55 41 57 41 56 e8 0e 55 f5 ff 48 83 c4 20 90 <0f> 0b cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90003a06bc0 EFLAGS: 00010286
RAX: 0000000000000088 RBX: dffffc0000000000 RCX: efbd12c4feea6d00
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 0000000000000180 R08: ffffc90003a06927 R09: 1ffff92000740d24
R10: dffffc0000000000 R11: fffff52000740d25 R12: ffff8880312a6510
R13: ffff88802a4ad040 R14: ffff88802a4ad040 R15: 0000000000000188
FS:  000055555b534500(0000) GS:ffff888125461000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbef80720c0 CR3: 000000007ae2a000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 skb_over_panic net/core/skbuff.c:219 [inline]
 skb_put+0x159/0x210 net/core/skbuff.c:2655
 skb_put_zero include/linux/skbuff.h:2788 [inline]
 set_ipsecrequest net/key/af_key.c:3532 [inline]
 pfkey_send_migrate+0x1270/0x2e50 net/key/af_key.c:3636
 km_migrate+0x155/0x260 net/xfrm/xfrm_state.c:2848
 xfrm_migrate+0x2140/0x2450 net/xfrm/xfrm_policy.c:4705
 xfrm_do_migrate+0x8ff/0xaa0 net/xfrm/xfrm_user.c:3150
 xfrm_user_rcv_msg+0x746/0xb20 net/xfrm/xfrm_user.c:3507
 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550
 xfrm_netlink_rcv+0x79/0x90 net/xfrm/xfrm_user.c:3529
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg net/socket.c:742 [inline]
 ____sys_sendmsg+0x972/0x9f0 net/socket.c:2592
 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646
 __sys_sendmsg net/socket.c:2678 [inline]
 __do_sys_sendmsg net/socket.c:2683 [inline]
 __se_sys_sendmsg net/socket.c:2681 [inline]
 __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbef819c799
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:00007ffe28231e98 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fbef8415fa0 RCX: 00007fbef819c799
RDX: 0000000000000000 RSI: 0000200000000380 RDI: 0000000000000004
RBP: 00007fbef8232c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbef8415fac R14: 00007fbef8415fa0 R15: 00007fbef8415fa0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:skb_panic+0x157/0x160 net/core/skbuff.c:214
Code: c7 60 24 dc 8c 48 8b 74 24 08 48 8b 54 24 10 8b 0c 24 44 8b 44 24 04 4d 89 e9 50 55 41 57 41 56 e8 0e 55 f5 ff 48 83 c4 20 90 <0f> 0b cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90003a06bc0 EFLAGS: 00010286
RAX: 0000000000000088 RBX: dffffc0000000000 RCX: efbd12c4feea6d00
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 0000000000000180 R08: ffffc90003a06927 R09: 1ffff92000740d24
R10: dffffc0000000000 R11: fffff52000740d25 R12: ffff8880312a6510
R13: ffff88802a4ad040 R14: ffff88802a4ad040 R15: 0000000000000188
FS:  000055555b534500(0000) GS:ffff888125461000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbef80720c0 CR3: 000000007ae2a000 CR4: 00000000003526f0


---
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