From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 5CE5C355F42; Wed, 30 Sep 2026 15:47:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790783246; cv=none; b=MJLJcAnacWmmYSQEuNtQ5G9bPmJennfDAyFa2O4xGRM/J8U0ZlPv4MzKSxkRF9Bu+xmpwFe5v4NqLcYd48KqVDgfTduaM9CeoHtqQ77E/PPChwQ3yH/OOADsp0hVSJdE3NpVlcIz0MUc9jFAY/8u7PFB8ZKW0ZXZpdDXuIhR++o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790783246; c=relaxed/simple; bh=LZo30F41h5NYy0KUhVhQ9/38NrHgxAnBs0hQuzhhWPQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=jv+LqZBlfGCwJSo/SXIS0sXXHgoCcP++8xtdxal0Is6z9q/AjREGAlWGUHCDLlcJ884lRS5l4DRAfyyu2edzVudLSJSULjgjFrY3GrBP+7AlavBNV1Kp4+LbnhQJocdq/T+Xwy0Len9C4XgbEfuwrlWMM0o4Os0vvajSPIG55PA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=qHfv6MVH; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="qHfv6MVH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 461D91F000FF; Wed, 30 Sep 2026 15:47:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790783242; bh=i76DWxkbzi/s/1STldtwXoP0XTMb32liXNMlg50XJdg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=qHfv6MVHYUC96qaL+FCNEneBh/WmBVkwM5ENKB6IFYRG3i2nDeGjrITXK8pPCytT5 5nExuUw6Yhrr0fc4tZ9iA7GP8sUgWPlSbJQscU+t04u0/sgUA99wIRUtipiFGkpLbe s+0Ega4rAWrJWQZow5hjVuTOB+ak0Kfw+PUbk4xI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Shardul Bankar , Xinyang Ge , Paolo Abeni , "Matthieu Baerts (NGI0)" , Jakub Kicinski Subject: [PATCH 5.10 330/595] mptcp: close race between scheduler and state change Date: Wed, 30 Sep 2026 17:23:43 +0200 Message-ID: <20260930152354.782072936@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152347.700140858@linuxfoundation.org> References: <20260930152347.700140858@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Paolo Abeni commit 42064de57fb83231fcc89663a94885f228a1ee53 upstream. The mptcp scheduler may race with subflow sockets state change: data transmission on the selected socket may fail and a later release could try to use mss_now reset to 0 for a divide operation. Address the issue by explicitly checking for the critical scenario. Fixes: c886d70286bf ("mptcp: do not queue data on closed subflows") Cc: stable@vger.kernel.org Reported-by: Shardul Bankar Reported-by: Xinyang Ge Closes: https://lore.kernel.org/20260525194828.1137119-1-shardul.b@mpiricsoftware.com Signed-off-by: Paolo Abeni Reviewed-by: Matthieu Baerts (NGI0) Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260917-net-mptcp-misc-fixes-7-3-rc4-v2-2-0cf5c72667c8@kernel.org Signed-off-by: Jakub Kicinski [ Note: moved the mss_now check in previous places before commit d9ca1de8c0cd ("mptcp: move page frag allocation in mptcp_sendmsg()") which is not in this version. ] Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: Greg Kroah-Hartman --- net/mptcp/protocol.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1381,7 +1381,7 @@ restart: } mptcp_set_timeout(sk, ssk); - if (copied) { + if (copied && mss_now) { tcp_push(ssk, msg->msg_flags, mss_now, tcp_sk(ssk)->nonagle, size_goal); @@ -1891,7 +1891,7 @@ static void mptcp_worker(struct work_str if (!mptcp_ext_cache_refill(msk)) break; } - if (copied) { + if (copied && mss_now) { tcp_push(ssk, msg.msg_flags, mss_now, tcp_sk(ssk)->nonagle, size_goal); WRITE_ONCE(msk->allow_infinite_fallback, false);