___sys_sendmsg+0xf3/0x170 net/socket.c:2467
 __sys_sendmmsg+0x195/0x470 net/socket.c:2553
 __do_sys_sendmmsg net/socket.c:2582 [inline]
 __se_sys_sendmmsg net/socket.c:2579 [inline]
 __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2579
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
------------[ cut here ]------------
WARNING: CPU: 0 PID: 14422 at lib/ref_tracker.c:38 spin_unlock_irqrestore include/linux/spinlock.h:404 [inline]
WARNING: CPU: 0 PID: 14422 at lib/ref_tracker.c:38 ref_tracker_dir_exit.cold+0x137/0x1e3 lib/ref_tracker.c:37
Modules linked in:
CPU: 0 PID: 14422 Comm: kworker/0:29 Not tainted 5.16.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events mptcp_worker
RIP: 0010:ref_tracker_dir_exit.cold+0x137/0x1e3 lib/ref_tracker.c:38
Code: 4c 89 ef e8 dd 7e a9 f8 4c 8b 3c 24 4c 39 fd 49 8b 07 0f 85 b5 00 00 00 e8 28 20 62 f8 48 8b 74 24 10 4c 89 e7 e8 1b 30 36 00 <0f> 0b e9 c7 97 e8 fa 4c 89 ff e8 ac 7e a9 f8 e9 d4 fe ff ff e8 92
RSP: 0000:ffffc90004d77b20 EFLAGS: 00010246
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000001 RSI: 0000000000000001 RDI: 0000000000000001
RBP: ffff88807c721c18 R08: 0000000000000001 R09: ffffffff8ffa2b2f
R10: 0000000000000001 R11: 000000000008808a R12: ffff88807c721bd0
R13: ffff88807c721c18 R14: ffff88807c721c18 R15: ffff88807c721c18
FS:  0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005637190ac600 CR3: 0000000073989000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __put_net+0x15/0x70 net/core/net_namespace.c:640
 put_net include/net/net_namespace.h:268 [inline]
 put_net_track include/net/net_namespace.h:342 [inline]
 __sk_destruct+0x6d2/0x920 net/core/sock.c:2042
 sk_destruct+0xbd/0xe0 net/core/sock.c:2058
 __sk_free+0xef/0x3d0 net/core/sock.c:2069
 sk_free+0x78/0xa0 net/core/sock.c:2080
 sock_put include/net/sock.h:1912 [inline]
 mptcp_worker+0x779/0xbb0 net/mptcp/protocol.c:2513
 process_one_work+0x9b2/0x1660 kernel/workqueue.c:2298
 worker_thread+0x65d/0x1130 kernel/workqueue.c:2445
 kthread+0x405/0x4f0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>