netdev - [syzbot] [mptcp?] WARNING in __mark_subflow_endp

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Message-ID: <685aebf7.a00a0220.2e5631.008d.GAE@google.com>
Date: Tue, 24 Jun 2025 11:18:31 -0700
From: syzbot <syzbot+c6e2db6fd15f31126b7a@...kaller.appspotmail.com>
To: davem@...emloft.net, edumazet@...gle.com, geliang@...nel.org, 
	horms@...nel.org, kuba@...nel.org, linux-kernel@...r.kernel.org, 
	martineau@...nel.org, matttbe@...nel.org, mptcp@...ts.linux.dev, 
	netdev@...r.kernel.org, pabeni@...hat.com, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [mptcp?] WARNING in __mark_subflow_endp_available (2)

Hello,

syzbot found the following issue on:

HEAD commit:    75f5f23f8787 Merge tag 'block-6.16-20250619' of git://git...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=140f8182580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4130f4d8a06c3e71
dashboard link: https://syzkaller.appspot.com/bug?extid=c6e2db6fd15f31126b7a
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-75f5f23f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7979df97154f/vmlinux-75f5f23f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/010807ef6fc8/bzImage-75f5f23f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c6e2db6fd15f31126b7a@...kaller.appspotmail.com

netlink: 8 bytes leftover after parsing attributes in process `syz.3.1789'.
netlink: 8 bytes leftover after parsing attributes in process `syz.3.1789'.
------------[ cut here ]------------
WARNING: CPU: 0 PID: 12059 at net/mptcp/pm_kernel.c:880 __mark_subflow_endp_available net/mptcp/pm_kernel.c:880 [inline]
WARNING: CPU: 0 PID: 12059 at net/mptcp/pm_kernel.c:880 __mark_subflow_endp_available+0x12e/0x140 net/mptcp/pm_kernel.c:876
Modules linked in:
CPU: 0 UID: 0 PID: 12059 Comm: syz.3.1789 Not tainted 6.16.0-rc2-syzkaller-00231-g75f5f23f8787 #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:__mark_subflow_endp_available net/mptcp/pm_kernel.c:880 [inline]
RIP: 0010:__mark_subflow_endp_available+0x12e/0x140 net/mptcp/pm_kernel.c:876
Code: 48 0f ab 9d 88 0a 00 00 5b 5d 41 5c 41 5d e9 d9 f8 4c f6 e8 64 d0 b3 f6 eb ca e8 5d d0 b3 f6 e9 60 ff ff ff e8 c3 f8 4c f6 90 <0f> 0b 90 e9 78 ff ff ff 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90
RSP: 0018:ffffc900036373d8 EFLAGS: 00010283
RAX: 00000000000057d6 RBX: 0000000000000000 RCX: ffffc9000d761000
RDX: 0000000000080000 RSI: ffffffff8b6f236d RDI: 0000000000000001
RBP: ffff888025d08b80 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffff888025d09608
R13: ffff888025d095b8 R14: ffff8880653cde80 R15: 0000000000000000
FS:  00007f1bc288a6c0(0000) GS:ffff8880d6753000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1bc2888fb8 CR3: 0000000064977000 CR4: 0000000000352ef0
DR0: 0000000000000007 DR1: 000000000000009b DR2: 00040000ffffffff
DR3: 0000000000000009 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 mptcp_nl_remove_subflow_and_signal_addr net/mptcp/pm_kernel.c:915 [inline]
 mptcp_pm_nl_del_addr_doit+0xaf4/0xed0 net/mptcp/pm_kernel.c:1013
 genl_family_rcv_msg_doit+0x209/0x2f0 net/netlink/genetlink.c:1115
 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
 genl_rcv_msg+0x55c/0x800 net/netlink/genetlink.c:1210
 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2534
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x53a/0x7f0 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1883
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg net/socket.c:727 [inline]
 ____sys_sendmsg+0xa95/0xc70 net/socket.c:2566
 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2620
 __sys_sendmsg+0x16d/0x220 net/socket.c:2652
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1bc198e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1bc288a038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f1bc1bb6080 RCX: 00007f1bc198e929
RDX: 000000002000c094 RSI: 0000200000000000 RDI: 0000000000000006
RBP: 00007f1bc1a10b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f1bc1bb6080 R15: 00007ffc06c0d828
 </TASK>


---
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