------------[ cut here ]------------
msk->pm.local_addr_used == 0
WARNING: net/mptcp/pm_kernel.c:1070 at __mark_subflow_endp_available net/mptcp/pm_kernel.c:1070 [inline], CPU#1: syz.3.487/7861
WARNING: net/mptcp/pm_kernel.c:1070 at mptcp_nl_remove_subflow_and_signal_addr net/mptcp/pm_kernel.c:1102 [inline], CPU#1: syz.3.487/7861
WARNING: net/mptcp/pm_kernel.c:1070 at mptcp_pm_nl_del_addr_doit+0xfb7/0x1420 net/mptcp/pm_kernel.c:1209, CPU#1: syz.3.487/7861
Modules linked in:
CPU: 1 UID: 0 PID: 7861 Comm: syz.3.487 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:__mark_subflow_endp_available net/mptcp/pm_kernel.c:1070 [inline]
RIP: 0010:mptcp_nl_remove_subflow_and_signal_addr net/mptcp/pm_kernel.c:1102 [inline]
RIP: 0010:mptcp_pm_nl_del_addr_doit+0xfb7/0x1420 net/mptcp/pm_kernel.c:1209
Code: 01 00 00 49 89 c6 e8 28 34 3e f6 e9 26 fb ff ff e8 1e 34 3e f6 48 89 df be 03 00 00 00 e8 91 73 1a f9 eb a4 e8 0a 34 3e f6 90 <0f> 0b 90 e9 ad fe ff ff 89 d9 80 e1 07 38 c1 0f 8c 12 fb ff ff 48
RSP: 0018:ffffc90003037160 EFLAGS: 00010287
RAX: ffffffff8b864346 RBX: 0000000000000000 RCX: 0000000000080000
RDX: ffffc9000c95b000 RSI: 00000000000028ea RDI: 00000000000028eb
RBP: ffffc900030373b0 R08: ffff88805705a3b7 R09: 1ffff1100ae0b476
R10: dffffc0000000000 R11: ffffed100ae0b477 R12: 1ffff1100ae0b475
R13: ffff888028e53d00 R14: ffff888057059900 R15: ffff88805705a3a8
FS:  00007f68579026c0(0000) GS:ffff8881257f5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001783 CR3: 0000000031672000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 genl_family_rcv_msg_doit+0x22a/0x330 net/netlink/genetlink.c:1115
 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
 genl_rcv_msg+0x61c/0x7a0 net/netlink/genetlink.c:1210
 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
 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+0xa68/0xad0 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+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f685699bf79
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:00007f6857902028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f6856c15fa0 RCX: 00007f685699bf79
RDX: 0000000000000000 RSI: 0000200000000140 RDI: 0000000000000007
RBP: 00007f6856a327e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6856c16038 R14: 00007f6856c15fa0 R15: 00007ffe26a7c398
 </TASK>