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 07A0A1E7C18; Sat, 19 Sep 2026 20:13:10 +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=1789848791; cv=none; b=h5vDbQ9d1XXpXSGK6vL0Cc9NKu+mXxJrmJf2ZHkcKoQjm8zJmfok1wXqWp/ijZaaF6nOe1OvdT9j0dM/6sJS0NoXCaDENiye8if/Qw99SzL4IbkEhOsHgZlZctFVn3ejcMNp/P1N5BULADfBhhnPxJbpE+1SRYsEs0qqmEoGAf8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789848791; c=relaxed/simple; bh=dwhocoWCq7rJOiLDrwA64Y6T/zGO94j072keG0FzDLM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RXmvYhpKA7PCsDJg9j+NtgBkZTakjoVrkgiv2SP/DjsjNhCPhIf9CuwiC+g3VS+ETKWolrNfRWJo3zEI74AMs54zapPKgLwHsAVv3siBpxPU3+Y1RPNehpF6gHoZayWt99FieLfZEofZkRXW1uhPCCygB2D9sfeBS3y3X3MYE7Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dGSmk6Fi; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="dGSmk6Fi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4A0711F00893; Sat, 19 Sep 2026 20:13:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789848789; bh=VGv5bcygaPAIYafDfFrgO8tRS847RoBkPdxQSzJbqEM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=dGSmk6Fib+CKh9hvVJMuflpifkMl0u7f7UXLTNN8MJDKAaiCMcpxom9LmIqDHWsvJ LihUGL0uF78KYkTsemKY9rIJsY8eTdExqEJzGeIAyNWBIEJ87GJr9x0+uGRH0AymQL QztpCcvYMOjdATw55Jpw6gv3q7nH36FPuvOKb8eGgkWRHLSiOcUNidqZzwZlCsd4ep wkyxU2mU9hH5o+UEUoO2ts6JjDwIK5tHYdic9dF4u6XeqEs7402FycYGcM41g9+v// QvIR2UFma5HHujlSlnyCck/uK7tTo+W8BKC3JUTYflK4PuzF27N8DIsvGmDMgsEs/v dmQ9EwUcFzRZw== From: "Matthieu Baerts (NGI0)" To: mptcp@lists.linux.dev, stable@vger.kernel.org, gregkh@linuxfoundation.org Cc: Paolo Abeni , sashal@kernel.org, Shardul Bankar , Xinyang Ge , "Matthieu Baerts (NGI0)" , Jakub Kicinski Subject: [PATCH 6.1.y 3/3] mptcp: close race between scheduler and state change Date: Sat, 19 Sep 2026 22:12:56 +0200 Message-ID: <20260919201252.2025112-8-matttbe@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260919201252.2025112-5-matttbe@kernel.org> References: <20260919201252.2025112-5-matttbe@kernel.org> Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1643; i=matttbe@kernel.org; h=from:subject; bh=YCaJS/uVeKh2uLBYtsClOmVMEQ7iEBR2miH8Bkb8vGg=; b=owGbwMvMwCVWo/Th0Gd3rumMp9WSGLLWvTm5fae/hR7DxOVbtx8u5EvTa9rwIuJMRYhbQy3jV EdOzr35HaUsDGJcDLJiiizSbZH5M59X8ZZ4+VnAzGFlAhnCwMUpABMxKWf47/3F4ULyAlcBI04N ERGuKX93PLFx81V8+N5bJ/5u8/VCLUaGfWv4K64W+Mx2tdoU7n30S1nXj/lpjF+0vJUfcP99b/y SDwA= X-Developer-Key: i=matttbe@kernel.org; a=openpgp; fpr=E8CB85F76877057A6E27F77AF6B7824F4269A073 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Matthieu Baerts (NGI0) --- net/mptcp/protocol.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index ab83cf46a8c3..ca78add7670d 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1636,7 +1636,9 @@ static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk) static void mptcp_push_release(struct sock *ssk, struct mptcp_sendmsg_info *info) { - tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, info->size_goal); + if (info->mss_now) + tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, + info->size_goal); release_sock(ssk); } -- 2.55.0