TCP: request_sock_subflow_v6: Possible SYN flooding on port [fe80::aa]:20002. Sending cookies.
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BUG: KMSAN: uninit-value in subflow_token_join_request net/mptcp/subflow.c:91 [inline]
BUG: KMSAN: uninit-value in subflow_check_req+0x1028/0x15d0 net/mptcp/subflow.c:209
 subflow_token_join_request net/mptcp/subflow.c:91 [inline]
 subflow_check_req+0x1028/0x15d0 net/mptcp/subflow.c:209
 subflow_v6_route_req+0x269/0x410 net/mptcp/subflow.c:367
 tcp_conn_request+0x14eb/0x4170 net/ipv4/tcp_input.c:7008
 subflow_v6_conn_request+0x3ee/0x510
 tcp_rcv_state_process+0x2d4/0x4990 net/ipv4/tcp_input.c:6509
 tcp_v6_do_rcv+0x12b8/0x1fd0 net/ipv6/tcp_ipv6.c:1510
 tcp_v6_rcv+0x47dc/0x4f80 net/ipv6/tcp_ipv6.c:1736
 ip6_protocol_deliver_rcu+0xda6/0x2a60 net/ipv6/ip6_input.c:437
 ip6_input_finish net/ipv6/ip6_input.c:482 [inline]
 NF_HOOK include/linux/netfilter.h:304 [inline]
 ip6_input+0x15d/0x430 net/ipv6/ip6_input.c:491
 dst_input include/net/dst.h:468 [inline]
 ip6_rcv_finish+0x5db/0x870 net/ipv6/ip6_input.c:79
 NF_HOOK include/linux/netfilter.h:304 [inline]
 ipv6_rcv+0xda/0x390 net/ipv6/ip6_input.c:309
 __netif_receive_skb_one_core net/core/dev.c:5523 [inline]
 __netif_receive_skb+0x1a6/0x5a0 net/core/dev.c:5637
 netif_receive_skb_internal net/core/dev.c:5723 [inline]
 netif_receive_skb+0x58/0x660 net/core/dev.c:5782
 tun_rx_batched+0x83b/0x920
 tun_get_user+0x564c/0x6940 drivers/net/tun.c:2002
 tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2048
 call_write_iter include/linux/fs.h:1985 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x8ef/0x15c0 fs/read_write.c:584
 ksys_write+0x20f/0x4c0 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x93/0xd0 fs/read_write.c:646
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Local variable mp_opt created at:
 subflow_check_req+0x6d/0x15d0 net/mptcp/subflow.c:145
 subflow_v6_route_req+0x269/0x410 net/mptcp/subflow.c:367

CPU: 1 PID: 19411 Comm: syz-executor.5 Not tainted 6.5.0-syzkaller-04592-gd68b4b6f307d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
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