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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_close_sync+0xbc/0x210 fs/file_table.c:615
 __do_sys_close fs/open.c:1507 [inline]
 __se_sys_close fs/open.c:1492 [inline]
 __ia32_sys_close+0xef/0x2c0 fs/open.c:1492
 ia32_sys_call+0x37cf/0x4360 arch/x86/include/generated/asm/syscalls_32.h:7
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0x195/0x470 arch/x86/entry/syscall_32.c:307
 do_fast_syscall_32+0x37/0x80 arch/x86/entry/syscall_32.c:332
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/syscall_32.c:370
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

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: 5918 Comm: syz.0.23 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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