syzbot

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BUG: KMSAN: uninit-value in mptcp_write_data_fin net/mptcp/options.c:542 [inline]
BUG: KMSAN: uninit-value in mptcp_established_options_dss net/mptcp/options.c:590 [inline]
BUG: KMSAN: uninit-value in mptcp_established_options+0x112f/0x3530 net/mptcp/options.c:874
 mptcp_write_data_fin net/mptcp/options.c:542 [inline]
 mptcp_established_options_dss net/mptcp/options.c:590 [inline]
 mptcp_established_options+0x112f/0x3530 net/mptcp/options.c:874
 tcp_established_options+0x312/0xcc0 net/ipv4/tcp_output.c:1192
 __tcp_transmit_skb+0x5dc/0x5fe0 net/ipv4/tcp_output.c:1575
 __tcp_send_ack+0x967/0xad0 net/ipv4/tcp_output.c:4500
 tcp_send_ack+0x3d/0x60 net/ipv4/tcp_output.c:4506
 mptcp_subflow_shutdown+0x164/0x690 net/mptcp/protocol.c:3151
 mptcp_check_send_data_fin+0x31b/0x3d0 net/mptcp/protocol.c:3232
 __mptcp_wr_shutdown net/mptcp/protocol.c:3248 [inline]
 __mptcp_close+0x860/0x1360 net/mptcp/protocol.c:3327
 mptcp_close+0x42/0x260 net/mptcp/protocol.c:3381
 inet_release+0x1ee/0x2a0 net/ipv4/af_inet.c:442
 __sock_release net/socket.c:722 [inline]
 sock_close+0xd6/0x2f0 net/socket.c:1514
 __fput+0x60e/0x1010 fs/file_table.c:510
 ____fput+0x25/0x30 fs/file_table.c:538
 task_work_run+0x208/0x2b0 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0x505/0x2420 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x261/0x3c0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Local variable opts created at:
 __tcp_transmit_skb+0x4d/0x5fe0 net/ipv4/tcp_output.c:1536
 __tcp_send_ack+0x967/0xad0 net/ipv4/tcp_output.c:4500

CPU: 1 UID: 0 PID: 5906 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
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