[v6.1] WARNING in mptcp_pm_alloc_anno_list

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: c27210688955 Linux 6.1.173
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=155fc6d2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b1adc0bfde2d8a4a
dashboard link: https://syzkaller.appspot.com/bug?extid=5e0e0d95c2a8aedfa034
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4cb5bf5356f0/disk-c2721068.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b3e6413ae0e6/vmlinux-c2721068.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6903bc5d334e/Image-c2721068.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5e0e0d...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 1 PID: 4615 at net/mptcp/pm_netlink.c:395 mptcp_pm_alloc_anno_list+0x2cc/0x328 net/mptcp/pm_netlink.c:-1
Modules linked in:
CPU: 1 PID: 4615 Comm: kworker/1:15 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Workqueue: events mptcp_worker
pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : mptcp_pm_alloc_anno_list+0x2cc/0x328 net/mptcp/pm_netlink.c:-1
lr : mptcp_pm_alloc_anno_list+0x2c8/0x328 net/mptcp/pm_netlink.c:395
sp : ffff800020a073c0
x29: ffff800020a073c0 x28: 0000000000000003 x27: dfff800000000000
x26: dfff800000000000 x25: 0000000000000001 x24: ffff700004140e9c
x23: ffff0000d83faf00 x22: 0000000000000000 x21: ffff0000ca8c6000
x20: ffff0000d42e1c40 x19: ffff0000d83faf00 x18: ffff800011b9bf60
x17: ffff80001835b000 x16: ffff8000082d7ed4 x15: 0000000000000000
x14: 0000000000000007 x13: 0000000000000000 x12: 0000000000ff0100
x11: ff008000118a8ab4 x10: 0000000000000000 x9 : ffff8000118a8ab4
x8 : ffff0000cb5a8000 x7 : ffff0000f2982300 x6 : ffff0000c308a040
x5 : ffff800020a07538 x4 : ffff0000f134dc38 x3 : ffff8000118b2e54
x2 : 0000000000000038 x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
mptcp_pm_alloc_anno_list+0x2cc/0x328 net/mptcp/pm_netlink.c:-1
mptcp_pm_create_subflow_or_signal_addr+0x103c/0x177c net/mptcp/pm_netlink.c:614
mptcp_pm_nl_subflow_established net/mptcp/pm_netlink.c:688 [inline]
mptcp_pm_nl_work+0x17f0/0x1d04 net/mptcp/pm_netlink.c:1060
mptcp_worker+0xc0/0x1208 net/mptcp/protocol.c:2847
process_one_work+0x7f8/0x13a4 kernel/workqueue.c:2292
worker_thread+0x8c4/0xfec kernel/workqueue.c:2439
kthread+0x250/0x2d8 kernel/kthread.c:376
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850
irq event stamp: 175397
hardirqs last enabled at (175395): [<ffff800011b23be4>] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
hardirqs last enabled at (175395): [<ffff800011b23be4>] _raw_spin_unlock_irqrestore+0x48/0xac kernel/locking/spinlock.c:194
hardirqs last disabled at (175397): [<ffff800011a38ab4>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:405
softirqs last enabled at (175390): [<ffff80000fd55e38>] spin_unlock_bh include/linux/spinlock.h:396 [inline]
softirqs last enabled at (175390): [<ffff80000fd55e38>] release_sock+0x16c/0x1bc net/core/sock.c:3522
softirqs last disabled at (175396): [<ffff8000118b1904>] spin_lock_bh include/linux/spinlock.h:356 [inline]
softirqs last disabled at (175396): [<ffff8000118b1904>] mptcp_pm_nl_rm_addr_or_subflow+0x3bc/0x984 net/mptcp/pm_netlink.c:993
---[ end trace 0000000000000000 ]---


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