From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5E128371D05; Thu, 7 May 2026 07:44:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778139882; cv=none; b=XwDuz/J5uUPchfJLIQ/bmouiIx2gHHjDVL62s/1BLdXyOoVp2LBYrQhuhbFMXlt7wu3CXAVbn6ecB7yK+JaD/FAmSFLJM1uJms5xM2EeGxsYA0y6cCxQrMANSnQXxib0xlsgb27T5VfmT2A/FiaNGKF4f4QC6wpJ33km1rxsbmc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778139882; c=relaxed/simple; bh=3SB4V4RXsUIQ3+bqYGeO7CBlxhBdDGQk9jVAIk1hsdY=; h=Message-ID:Date:MIME-Version:Subject:To:References:From:Cc: In-Reply-To:Content-Type; b=DftAWX4WmKf9bEKU1yxm5GJECGPaijQkQZE0dBqe9dDip+k1Fi07TDhgmUZHAHZlRXZXIS/6gWrAtt7qfZlWqKaKWrq2hzAZ642Vq3wobhCUuvgrRFUYwwUnMnEg/FyGORHF8WMe+priuf4n4f4Eqg/5AQHWjDiUiVw0EPWlMZI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TVu6K0hM; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TVu6K0hM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8AA78C2BCB8; Thu, 7 May 2026 07:44:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778139881; bh=3SB4V4RXsUIQ3+bqYGeO7CBlxhBdDGQk9jVAIk1hsdY=; h=Date:Subject:To:References:From:Cc:In-Reply-To:From; b=TVu6K0hM84GRFjkw7FrwNE5pt9hE+W+dyOmUaPhBvum9UqEhxgmCeS7IHoB0ySaji yRu2eyw/XwYfMJ6g3v66xGlJDy/4p0RiHWVbe230xZuH32z7cYuYuo+t2B3SNtd4gg Cf+t22dTBXvvAfCRGZqKJFOaEsEgU8NH6ec3ycpia4g5Zqm53o0Bl5IHdUmB/PZSbb yuNYnF30KGbvS68PIIgHDYZIno2ioqURabZ0xGiQM+Y+/BqPHcR55qj7IcZvs+Gked n54aRJHNbt4jn9q+G3OLwtXh2oXZ0haZh+FArpWDy8xTJzMzJ+gYR9qJ+sPaqF8gF/ HQ31484Im5JbA== Message-ID: <2a9bde65-d2de-44cc-9192-e7aa8a0935a7@kernel.org> Date: Thu, 7 May 2026 09:44:37 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [syzbot] [mptcp?] KMSAN: uninit-value in mptcp_established_options Content-Language: fr To: kuniyu@google.com, pabeni@redhat.com References: <69f8e352.170a0220.bb392.0005.GAE@google.com> From: Matthieu Baerts Cc: syzbot , linux-kernel@vger.kernel.org, mptcp@lists.linux.dev, syzkaller-bugs@googlegroups.com Autocrypt: addr=matttbe@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Paolo, Kuniyuki, On 04/05/2026 20:20, syzbot wrote: > Hello, > > syzbot has tested the proposed patch but the reproducer is still triggering an issue: > KMSAN: uninit-value in irqentry_exit_to_kernel_mode_preempt It looks like the issue is different now: > ===================================================== > BUG: KMSAN: uninit-value in irqentry_exit_to_kernel_mode_preempt+0xb0/0xc0 include/linux/irq-entry-common.h:472 > irqentry_exit_to_kernel_mode_preempt+0xb0/0xc0 include/linux/irq-entry-common.h:472 > irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline] > irqentry_exit+0x7b/0x760 kernel/entry/common.c:164 > sysvec_apic_timer_interrupt+0x52/0x90 arch/x86/kernel/apic/apic.c:1061 > asm_sysvec_apic_timer_interrupt+0x1f/0x30 arch/x86/include/asm/idtentry.h:697 > kmsan_get_metadata+0x17/0x160 mm/kmsan/shadow.c:125 > kmsan_get_shadow_origin_ptr+0x4a/0xb0 mm/kmsan/shadow.c:102 > get_shadow_origin_ptr mm/kmsan/instrumentation.c:38 [inline] > __msan_metadata_ptr_for_load_4+0x24/0x40 mm/kmsan/instrumentation.c:93 > tcp_data_queue+0xdc/0x7c90 net/ipv4/tcp_input.c:5589 > tcp_rcv_established+0x19bb/0x3200 net/ipv4/tcp_input.c:6656 > tcp_v4_do_rcv+0xc4b/0x1b10 net/ipv4/tcp_ipv4.c:1852 > sk_backlog_rcv include/net/sock.h:1190 [inline] That's the input side. > __release_sock+0x360/0x7d0 net/core/sock.c:3216 > release_sock+0x22d/0x300 net/core/sock.c:3815 > mptcp_subflow_shutdown+0x358/0x690 net/mptcp/protocol.c:3144 > 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_syscall_64+0x236/0xf80 arch/x86/entry/syscall_64.c:100 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > > Local variable mp_opt created at: > mptcp_incoming_options+0x11d/0x43b0 net/mptcp/options.c:1171 Confirmed here. With "struct mptcp_options_received" while the original issue was with "struct mptcp_out_options". Plus I'm not exactly sure to understand the issue here: mp_opt is defined and used only in mptcp_incoming_options(), and I don't see anything using it after the end of this function. Or did I miss something? Cheers, Matt -- Sponsored by the NGI0 Core fund.