------------[ cut here ]------------
WARNING: CPU: 0 PID: 16110 at net/mptcp/subflow.c:1520 subflow_data_ready+0x4b8/0x7e0
Modules linked in:
CPU: 0 UID: 0 PID: 16110 Comm: syz.1.2636 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:subflow_data_ready+0x4b8/0x7e0
Code: 0f 0b 90 90 e9 bc fc ff ff e8 74 b3 60 f6 48 89 df 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d e9 6e 0e 00 00 e8 59 b3 60 f6 90 <0f> 0b 90 e9 e5 fd ff ff 90 0f 0b 90 43 0f b6 04 2f 84 c0 0f 85 a1
RSP: 0018:ffffc90000007160 EFLAGS: 00010246
RAX: ffffffff8b5efa37 RBX: ffff888011bfe800 RCX: ffff888107c45640
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff88811c40d137 R09: 1ffff11023881a26
R10: dffffc0000000000 R11: ffffed1023881a27 R12: 0000000000000000
R13: dffffc0000000000 R14: ffff88811c40c800 R15: 0000000000000000
FS:  00007fc7382116c0(0000) GS:ffff8880b863d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000005000 CR3: 0000000040106000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 tcp_data_queue+0x54b/0x6450
 tcp_rcv_state_process+0x2396/0x43b0
 tcp_v4_do_rcv+0x3f2/0xce0
 tcp_v4_rcv+0x252a/0x2dc0
 ip_protocol_deliver_rcu+0x221/0x440
 ip_local_deliver_finish+0x3bb/0x6f0
 NF_HOOK+0x30c/0x3a0
 NF_HOOK+0x30c/0x3a0
 __netif_receive_skb+0x143/0x380
 process_backlog+0x60e/0x14f0
 __napi_poll+0xc7/0x360
 net_rx_action+0x707/0xe30
 handle_softirqs+0x286/0x870
 __irq_exit_rcu+0xca/0x1f0
 irq_exit_rcu+0x9/0x30
 sysvec_apic_timer_interrupt+0xa6/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:netlink_attachskb+0x0/0xa60
Code: 38 c1 0f 8c 73 ff ff ff 4c 89 ff e8 ea cc 81 f8 e9 66 ff ff ff 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48
RSP: 0018:ffffc90002acf538 EFLAGS: 00000246
RAX: ffffffff89a171df RBX: ffff888027af3030 RCX: ffff888027af3000
RDX: ffffc90002acf598 RSI: ffff88810b5a5200 RDI: ffff8880417a8000
RBP: ffffc90002acf630 R08: 0000000000000000 R09: ffffffff896c74a0
R10: dffffc0000000000 R11: ffffed10082f50ae R12: ffff88810b5a5200
R13: 0000000000000000 R14: ffff8880417a8000 R15: 0000000000000000
 netlink_unicast+0x2cd/0x9e0
 netlink_rcv_skb+0x28c/0x470
 genl_rcv+0x28/0x40
 netlink_unicast+0x82f/0x9e0
 netlink_sendmsg+0x805/0xb30
 __sock_sendmsg+0x21c/0x270
 ____sys_sendmsg+0x505/0x830
 ___sys_sendmsg+0x21f/0x2a0
 __x64_sys_sendmsg+0x19b/0x260
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc73738ec29
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:00007fc738211038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fc7375d5fa0 RCX: 00007fc73738ec29
RDX: 0000000020000000 RSI: 0000200000000140 RDI: 000000000000000b
RBP: 00007fc737411e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc7375d6038 R14: 00007fc7375d5fa0 R15: 00007ffef42503d8
 </TASK>
