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 8E78C34A79D; Sun, 13 Sep 2026 10:30:25 +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=1789295425; cv=none; b=fz/HSkgBNU0wa5UjtcVRQyRlmYwmUvl38QU8yvg/5b/bp/7vknav3C6KeDqk4zxFiAfr87EDEJ+fwghCelovlIBNCPBjJA6b44E91chWZI8chq4Ep0YMjaIEyrH40pUAHFuQvxm4fR/AmWCnU+8aTkefZJxeBYe7PtMxru7MNFE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789295425; c=relaxed/simple; bh=ngCDj8Emz3p32EELUtISMOwDZrHYeIZwMySzMY+65J4=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:To:Cc; b=BJj/mto/Ktlq89LY6c15/RN9yTPr2fpq8PXUelmP/2+UWkVQ3hhlY9udlDzXCIw89MdxJkOwzggGYF/pfuHw40wQC1VpbU2vdCouyUPE9peVEAAT4LCgEYxiC8W6NLVsllj8pfqqSbglJN3SgJcTt63W/nfisYy+eLOsMl+CxFo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=qj/94uDh; 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="qj/94uDh" Received: by smtp.kernel.org (Postfix) with ESMTPS id 7494CC2BCC7; Sun, 13 Sep 2026 10:30:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1789295424; bh=ngCDj8Emz3p32EELUtISMOwDZrHYeIZwMySzMY+65J4=; h=From:Date:Subject:To:Cc:Reply-To:From; b=qj/94uDh5MMmNZHdT5ndhFtT9gGUmofzZeqyAwYWAabRyNpJbh+3VXeYroEVIyr/L eK63bu89IzoYAfzqDgfzuRDEze8SaiS1IKAvWONtkGsqRuYuOrJPkL8JKfM6PM3Oeq HnpSvl3bgndDt8752AGa2OJKIuy8EYGjZEG80/fhXRjiGTR3L68MSC2913b+t0GUQM NmCmQjz03xwe5/5Rt+kA8XHb/nLfdZ/FKJwdS603BG62mhGEl7vi4q/YWxQa0H5iHE k6tn2ptUz4ecPXj/3ECw36GQoYbioYBrLd2EDzVac36sTCcy1MWY+nQoSCR8KJNdrH 0G+sVWQ1+XHUg== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4E120C88E56; Sun, 13 Sep 2026 10:30:24 +0000 (UTC) From: Mark Amirkan via B4 Relay Date: Sun, 13 Sep 2026 10:30:05 +0000 Subject: [PATCH net] mptcp: return sk_wait_data() errors from recvmsg() Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260913-b4-send-mptcp-recv-error-v1-1-4eaa3684a8b8@gmail.com> X-B4-Tracking: v=1; b=H4sIAC17pmoC/yWMwQ6CMBAFf4Xs2U0KqAF/xXCQ5VXXxNJsKyEh/ LtVjzPJzEYJpkh0qTYyLJp0DgXqQ0XyuIU7WKfC1Ljm7Pq65fHICWHiV8wS2SALw2w2hne+6zu 4kwiVPBq8rr/1lQIyDX+Z3uMTkr9T2vcPxYYZLIEAAAA= X-Change-ID: 20260913-b4-send-mptcp-recv-error-ef0f898e05cc To: Matthieu Baerts , Mat Martineau , mptcp@lists.linux.dev Cc: Jakub Kicinski , Geliang Tang , "David S. Miller" , Simon Horman , linux-kernel@vger.kernel.org, Paolo Abeni , netdev@vger.kernel.org, Eric Dumazet X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1789295423; l=1552; i=markdamirkan@gmail.com; s=pscsi-20260818; h=from:subject:message-id; bh=nFns6QPwNtc6ZlWxL0DfCPRqrLoyi61MO8NmnrCReZ0=; b=zUnCB4O2oj2YTonWyuK6Qcw/TnT5pXlznkPJPKBbwLfP6dmUgoy5JYhplV6fjLQ/c/NfTunoJ yPRzcwrZ8Q8A6ln++W+b0owuF5pCAcU12geosagpf0liSbGaRVjlZH4 X-Developer-Key: i=markdamirkan@gmail.com; a=ed25519; pk=/wb49ibt4gZFDncmhFQBYtjPvzT1tfJtvK4Mqt1P2Wc= X-Endpoint-Received: by B4 Relay for markdamirkan@gmail.com/pscsi-20260818 with auth_id=961 X-Original-From: Mark Amirkan Reply-To: markdamirkan@gmail.com From: Mark Amirkan Commit 581302298524 ("mptcp: error out earlier on disconnect") made mptcp_recvmsg() stop when sk_wait_data() returns an error. The error is stored in err, but the function then jumps to a path which returns copied. When no data was copied, recvmsg() therefore returns zero and reports a false EOF. Store the result in copied, which is the value returned by the function. This also keeps the usual partial-read result when data was copied before the error. A recvmsg() blocked in one thread reproduces the issue when another thread disconnects the same MPTCP socket with connect(AF_UNSPEC). Before this change recvmsg() returns zero; afterwards it returns -EPIPE. Fixes: 581302298524 ("mptcp: error out earlier on disconnect") Cc: stable@vger.kernel.org Assisted-by: Symbolic Signed-off-by: Mark Amirkan --- net/mptcp/protocol.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 0098e28309..8dc25ef154 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2459,7 +2459,7 @@ static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, mptcp_cleanup_rbuf(msk, copied); err = sk_wait_data(sk, &timeo, last); if (err < 0) { - err = copied ? : err; + copied = copied ? : err; goto out_err; } } --- base-commit: 78445023439506ebd83b86d40b1e428a3b309d4a change-id: 20260913-b4-send-mptcp-recv-error-ef0f898e05cc Best regards, -- Mark Amirkan