syzbot

TCP: request_sock_subflow_v4: Possible SYN flooding on port 20002. Sending cookies.  Check SNMP counters.
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WARNING: CPU: 0 PID: 7542 at net/mptcp/protocol.c:705 __mptcp_move_skbs_from_subflow+0x2025/0x2130
Modules linked in:
CPU: 0 PID: 7542 Comm: syz.0.1052 Not tainted 6.1.104-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
RIP: 0010:__mptcp_move_skbs_from_subflow+0x2025/0x2130 net/mptcp/protocol.c:705
Code: 40 80 e5 01 40 0f b6 dd 31 ff 89 de e8 b4 00 f8 f6 89 d8 48 81 c4 68 01 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 3b fe f7 f6 <0f> 0b eb ab e8 32 fe f7 f6 43 0f b6 04 2c 84 c0 0f 85 85 00 00 00
RSP: 0018:ffffc90000006e60 EFLAGS: 00010246
RAX: ffffffff8a92a1c5 RBX: 0000000000007d00 RCX: ffff888020408000
RDX: 0000000080000303 RSI: 00000000000081e5 RDI: 0000000000007d00
RBP: 00000000000081e5 R08: ffffffff8a929210 R09: ffffed100f1311c3
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000020000
R13: dffffc0000000000 R14: ffff88801b65e85c R15: ffff888078988e10
FS:  00007f093bdff6c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020100000 CR3: 000000004bb9b000 CR4: 00000000003506f0
Call Trace:
 <IRQ>
 move_skbs_to_msk net/mptcp/protocol.c:818 [inline]
 mptcp_data_ready+0x203/0x790 net/mptcp/protocol.c:861
 subflow_data_ready+0x254/0x390 net/mptcp/subflow.c:1361
 tcp_data_queue+0x21c5/0x6fd0 net/ipv4/tcp_input.c:5138
 tcp_rcv_established+0xe63/0x1f00 net/ipv4/tcp_input.c:6064
 tcp_v4_do_rcv+0x487/0xb00 net/ipv4/tcp_ipv4.c:1678
 tcp_v4_rcv+0x29e0/0x3250 net/ipv4/tcp_ipv4.c:2109
 ip_protocol_deliver_rcu+0x381/0x740 net/ipv4/ip_input.c:205
 ip_local_deliver_finish+0x304/0x580 net/ipv4/ip_input.c:233
 NF_HOOK+0x39d/0x450 include/linux/netfilter.h:302
 NF_HOOK+0x39d/0x450 include/linux/netfilter.h:302
 __netif_receive_skb_one_core net/core/dev.c:5528 [inline]
 __netif_receive_skb+0x1c6/0x530 net/core/dev.c:5642
 process_backlog+0x381/0x760 net/core/dev.c:5970
 __napi_poll+0xc7/0x470 net/core/dev.c:6537
 napi_poll net/core/dev.c:6604 [inline]
 net_rx_action+0x70f/0xeb0 net/core/dev.c:6718
 handle_softirqs+0x2ee/0xa40 kernel/softirq.c:571
 do_softirq+0x162/0x240 kernel/softirq.c:472
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x1b1/0x1f0 kernel/softirq.c:396
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:861 [inline]
 __dev_queue_xmit+0x1790/0x3cf0 net/core/dev.c:4320
 dev_queue_xmit include/linux/netdevice.h:3021 [inline]
 neigh_hh_output include/net/neighbour.h:528 [inline]
 neigh_output include/net/neighbour.h:542 [inline]
 ip_finish_output2+0xcfc/0x1330 net/ipv4/ip_output.c:228
 dst_output include/net/dst.h:444 [inline]
 ip_local_out net/ipv4/ip_output.c:126 [inline]
 __ip_queue_xmit+0x11b1/0x1b60 net/ipv4/ip_output.c:532
 __tcp_transmit_skb+0x1e33/0x33a0 net/ipv4/tcp_output.c:1403
 tcp_transmit_skb net/ipv4/tcp_output.c:1421 [inline]
 tcp_mtu_probe net/ipv4/tcp_output.c:2457 [inline]
 tcp_write_xmit+0x5d7a/0x64c0 net/ipv4/tcp_output.c:2633
 __tcp_push_pending_frames+0x97/0x350 net/ipv4/tcp_output.c:2894
 mptcp_push_release net/mptcp/protocol.c:1557 [inline]
 __mptcp_push_pending+0x734/0xd50 net/mptcp/protocol.c:1635
 mptcp_sendmsg+0x1469/0x1840 net/mptcp/protocol.c:1888
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 __sys_sendto+0x480/0x600 net/socket.c:2148
 __do_sys_sendto net/socket.c:2160 [inline]
 __se_sys_sendto net/socket.c:2156 [inline]
 __x64_sys_sendto+0xda/0xf0 net/socket.c:2156
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f093bf799f9
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:00007f093bdff038 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f093c115f80 RCX: 00007f093bf799f9
RDX: 0000000000100b20 RSI: 0000000020000040 RDI: 0000000000000005
RBP: 00007f093bfe78ee R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f093c115f80 R15: 00007ffc7e18e9a8
 </TASK>