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 60E8141C30A; Wed, 4 Feb 2026 15:00:04 +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=1770217204; cv=none; b=aXFMEg/vKcOnM/TCedIf0nDnxsv70hHaYXzMQ+d9+GEYZ4tKllyHVVDJrS1SvdUXZtyKHAEhJlRpswsVj4iP8MxAJ9/YpaOakOwfBvdCZgdD07JoKyI+6xP1z5qA4A69pJTlor7T7wImW23S1PHxnMFlxdFoKb8hI2nGbFgwHXw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770217204; c=relaxed/simple; bh=kq60KMYS516k86qcjSmktTQqpUwfDK8yPTSwaY1RQ0M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=brDCQi+K5DPJlDFOAnqf9nue0KZkF3+CuGNqaV0dh38Ue2COSACw+j9z4phJYKqK/YW8h746pOpXWGXOiD0KNYjI/7cJQqA1Acdr1z6iphBWFV0dCTAR05ld2Lx/JQvpk8E8caWXqo9+s2voqsWrpfCJ/d2zacXyz3zFv4ydw2o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=RoFS9NYR; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="RoFS9NYR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 48660C4CEF7; Wed, 4 Feb 2026 15:00:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1770217203; bh=kq60KMYS516k86qcjSmktTQqpUwfDK8yPTSwaY1RQ0M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RoFS9NYRntViBhcMobwwCboJ3ZoJD4fPdX1I2eTlQYlpteSPr12B7iz7OMBx+tUfm ItK2+cmdlWPQGrG2gkW4EOPnNNLNfsIulFw/uJqvzN3SonK62M6r/u5qeOUc3IM821 U2ztEH/V12jnGF+CRT07xDYsxx9DWt4nn/z9Q560= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Geliang Tang , "Matthieu Baerts (NGI0)" , Jakub Kicinski Subject: [PATCH 5.15 154/206] mptcp: only reset subflow errors when propagated Date: Wed, 4 Feb 2026 15:39:45 +0100 Message-ID: <20260204143903.748164137@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260204143858.193781818@linuxfoundation.org> References: <20260204143858.193781818@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Matthieu Baerts (NGI0) commit dccf46179ddd6c04c14be8ed584dc54665f53f0e upstream. Some subflow socket errors need to be reported to the MPTCP socket: the initial subflow connect (MP_CAPABLE), and the ones from the fallback sockets. The others are not propagated. The issue is that sock_error() was used to retrieve the error, which was also resetting the sk_err field. Because of that, when notifying the userspace about subflow close events later on from the MPTCP worker, the ssk->sk_err field was always 0. Now, the error (sk_err) is only reset when propagating it to the msk. Fixes: 15cc10453398 ("mptcp: deliver ssk errors to msk") Cc: stable@vger.kernel.org Reviewed-by: Geliang Tang Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260127-net-mptcp-dup-nl-events-v1-3-7f71e1bc4feb@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/mptcp/protocol.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -736,11 +736,8 @@ static bool __mptcp_ofo_queue(struct mpt static bool __mptcp_subflow_error_report(struct sock *sk, struct sock *ssk) { - int err = sock_error(ssk); int ssk_state; - - if (!err) - return false; + int err; /* only propagate errors on fallen-back sockets or * on MPC connect @@ -748,6 +745,10 @@ static bool __mptcp_subflow_error_report if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(mptcp_sk(sk))) return false; + err = sock_error(ssk); + if (!err) + return false; + /* We need to propagate only transition to CLOSE state. * Orphaned socket will see such state change via * subflow_sched_work_if_closed() and that path will properly