From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f80.google.com (mail-oo1-f80.google.com [209.85.161.80]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C86CC23EA8B for ; Fri, 1 May 2026 06:15:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.80 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777616136; cv=none; b=YokKCzdIe+DIIsnPSd2i2LyFjUO1unMPU1hgW9hc0/AisDw1YZwssYw23/jHL9BVNpq0oIyOaVpPtF0oEB3SMXxbeiWX9dxlpfst5FM/6g9u9GpLWWyALtkLCxDki6LaVjbih8lwiWQpcBkF0djB/Hiw0yx9mnhVTYt9sETY3Fg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777616136; c=relaxed/simple; bh=qZ4WU2pBlLmoGsXwq3Ezn4egfYWE9pBO/xwux0q5+PY=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=beqC/HxUaNPXZHve0+LDXRqxmAWm+b6e4mhspqAlT5y97qBowIF2gp6OfYlOndbB0EL+9eMyZVdf7tpNZkWfZzSdWLoQ3Uk5CmRz7FkMqZHz4XjoipWf2dqODrKLDHcD+EDfvEmndtT5hohiiLCXd5cTHNpM/I90v2aWJBfEOt8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.161.80 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oo1-f80.google.com with SMTP id 006d021491bc7-6966db8db2aso2973019eaf.0 for ; Thu, 30 Apr 2026 23:15:34 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1777616134; x=1778220934; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=vnYtTOTH4t5DEazx+JuK0nr+p0ULTXMDrk/Z6Bp4+xc=; b=Y5cssZi3Epxp7O/nlKP/8RVo1n3XCfKBvYGvX2KW/3I2uUlSxNUqkXaamIGZQAOhQg h+kv2j9WpDy9Q0gIZpEyBTrDbCBwf8JvBFLO7GVKSozzVsbn+CnsZR5pcK0bEuP2RUot 8RqaI6y3eS2EVKW77SpXTsg5riWGIOLrkODdrMIIyPMYLuCD10Tq3jG8Bgh0k3FXncKX UzPkKLl5xkSWRFDSZ6buUk6m/jxAyy7/CJ3eykZJSOknytiZJtko+T07PJmTsUfvXppj OmPH6SrHp1xdycKUB0mWN/LVIJ5sqvR8LG/L0e0fuMu+GMqoUyi1ISfL5kugOvU23bKk dzvQ== X-Forwarded-Encrypted: i=1; AFNElJ/s8YirUiLTCHlVtoZ70iEm775D1dKZXzg/zeAvaDTlw9/B0Sbpu7ijHS7IWHPcqL37PCzDzvI=@vger.kernel.org X-Gm-Message-State: AOJu0Yxlb9ekelSi1upyKZJYqhFDQy88drJqG0z25cvHpNTTIWWoLPbu yk95qre/91Xv8ImbcCh5XvmFEFFGclbmTQKtNsQXTRYvlcZkQGAaeLhN5tQOfrrlxZuWMvOar25 rjEtwhJt3InztTLmkieoPJ/0ajq8NZD5BK7xq3ANrgFrZwEX+q+tRC3XaHBc= Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:160a:b0:694:95ae:c546 with SMTP id 006d021491bc7-6967bcc8597mr2734595eaf.2.1777616133780; Thu, 30 Apr 2026 23:15:33 -0700 (PDT) Date: Thu, 30 Apr 2026 23:15:33 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69f44505.050a0220.3cbe47.0008.GAE@google.com> Subject: [syzbot] [mptcp?] KMSAN: uninit-value in mptcp_established_options From: syzbot To: davem@davemloft.net, edumazet@google.com, geliang@kernel.org, horms@kernel.org, kuba@kernel.org, linux-kernel@vger.kernel.org, martineau@kernel.org, matttbe@kernel.org, mptcp@lists.linux.dev, netdev@vger.kernel.org, pabeni@redhat.com, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 08d0d3466664 Merge tag 'net-7.1-rc2' of git://git.kernel.o.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=15f6976c580000 kernel config: https://syzkaller.appspot.com/x/.config?x=1c3f61154f3bb7e5 dashboard link: https://syzkaller.appspot.com/bug?extid=ff020673c5e3d94d9478 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 userspace arch: i386 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/8688db3eb9ae/disk-08d0d346.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/72c570681077/vmlinux-08d0d346.xz kernel image: https://storage.googleapis.com/syzbot-assets/21669c9bddcd/bzImage-08d0d346.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+ff020673c5e3d94d9478@syzkaller.appspotmail.com ===================================================== 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:4499 tcp_send_ack+0x3d/0x60 net/ipv4/tcp_output.c:4505 mptcp_subflow_shutdown+0x164/0x690 net/mptcp/protocol.c:3137 mptcp_check_send_data_fin+0x31b/0x3d0 net/mptcp/protocol.c:3218 __mptcp_wr_shutdown net/mptcp/protocol.c:3234 [inline] __mptcp_close+0x860/0x1360 net/mptcp/protocol.c:3313 mptcp_close+0x42/0x260 net/mptcp/protocol.c:3367 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+0x306/0x1b60 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:238 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] __do_fast_syscall_32+0x2c7/0x460 arch/x86/entry/syscall_32.c:310 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:4499 CPU: 0 UID: 0 PID: 24584 Comm: syz.4.6812 Tainted: G W syzkaller #0 PREEMPT(full) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 ===================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup