From nobody Fri Dec 27 06:05:40 2024 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 D2D1E19C57C; Tue, 19 Nov 2024 08:35:58 +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=1732005359; cv=none; b=OTPNx1HDg1CfH0IkXlE4p62BwQjaR2JfqKCu51yGP5gdfpw3N5YCFWzrn7jDpSUwQFJyOX9yrFsacSCNyc6x5A6yAVshY7PvldgmKa73WrAbIJT4qfegGTzN3lAdm8Gzum2/TqSobyFq0oFAFC8NLj1O5Z++M7yviypiAz6pvBw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732005359; c=relaxed/simple; bh=SVigSOPIPTXyWyW3BHK5VjXaJj/wyC6EsOpbOIAqhW8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=cn3+WCEjMEzxyK10JmoFdzf1eOSPaNjXk8bR80DpWRMABHzzX5gYsPefOKMHfBLtj4EPg95gq5GMDWUZ55FYyXnaeoSMDQsvbDd+CDP8uAfztwjtmhOObbD25EdQLVEJx62Qr+EGLDjNu/vJAJOndnPXi8bg/JUCinNbdfoDpb4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=rLCddbFR; 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="rLCddbFR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C905BC4CED1; Tue, 19 Nov 2024 08:35:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1732005358; bh=SVigSOPIPTXyWyW3BHK5VjXaJj/wyC6EsOpbOIAqhW8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rLCddbFR9XKjSisnOP68hCYBjwOcauLCCI/5Mjx5tNKI1bjlHBlCQ/u6GyN00oq3I qVT3dOpbCzql0WAHDxCICRXr2baLp+tRQizrjZVdD7UYq9Vo0d5U2JfrWpLuOR/YYr TVN216mHn+Uruo1UhYA6YhXYDAeY67pr0a+n2y18LlZNXpg3K/ov66j2F9iCIHXsyU kngOKRTtWW2Ws16zj3YhJoOFG/PfKpGA54IVVvZ2NPbu7HQJz7zmOLxnxnMZPL8Qde 3j8g1LweJ8E0QQPF6dHz1X8VvJ7h53+kGLHm9BIZK7c9Ooef1yQbG1qYwSVVNCInpw pTEE5UA52ZNYg== From: "Matthieu Baerts (NGI0)" To: mptcp@lists.linux.dev, stable@vger.kernel.org, gregkh@linuxfoundation.org Cc: Paolo Abeni , sashal@kernel.org, Matthieu Baerts , Jakub Kicinski Subject: [PATCH 6.1.y 1/7] mptcp: cope racing subflow creation in mptcp_rcv_space_adjust Date: Tue, 19 Nov 2024 09:35:49 +0100 Message-ID: <20241119083547.3234013-10-matttbe@kernel.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20241119083547.3234013-9-matttbe@kernel.org> References: <20241119083547.3234013-9-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=1792; i=matttbe@kernel.org; h=from:subject; bh=NsYKbmCRaB8Vh/E7YFJfPDwZvCqJdiPN1sl2VILwj2I=; b=owEBbQKS/ZANAwAIAfa3gk9CaaBzAcsmYgBnPE3jgfPmg0lZ3X480DwZ5pHtLcNIkzaLE7c3u fmnp0fQx0yJAjMEAAEIAB0WIQToy4X3aHcFem4n93r2t4JPQmmgcwUCZzxN4wAKCRD2t4JPQmmg cxL+D/9g3IfLS3G6xyH4MgL/eXC6TXEfLs2nXWQFcXroMVEiJOUNBBXlWV8sTr/EY/xFrwirJf7 J888HhFrP8g4F6Ri3ZlBzr2/QCQCKz4SDEuXAwLnigdU8b8JHpv4g/V4JKCsPbdKjQtEW5/MwPZ iRHXs6jrQBQZf01i0asqgR3Qc4gq2nl2EX8BNLX5FfdVrNW0Evl1Zrk9MPNFnj8vmSJri1a9Jc3 KW/dih115JPnQCfMbAmoFNOhktVjWQxJtWEy6Q0C+kKSMJAHl3TM9JhGOHN2IFdz6tUvv46oTST xfKhxAAtnvq+6j+PcV/FWnGZfcie4TLi7enQBpFPiRtJP79LdddUnKefmxRbBSDXi6FT2+LuM7J dsyHN3nPPnbNjcn9cUGu5VELITL66D6/212/SozrfQZJqN72YE+zM+uOr/G+uPgGxNDUf3xHAYN +YVUTixSRSRo0pVflWDk30RP57BpOhKBWkc6zFfAmrhsJtdddZN6HBlWv7Y033fVxyVgjcbWrcJ pwUyvUbRevECgLO4Qja4lr9wkRarfZLUyFULAo1RW/QsPfHK8IBi3aE5JXSztwVRp4tPGK7F47+ BfYodf/gfuUMdXWIy/ade6JBkHtu5JhjRGBvWBnDR4OQTxOhK2ylgw0EKhq4r5xfS5l8B8DgkQR Tj0D7cAd7IVH9Og== X-Developer-Key: i=matttbe@kernel.org; a=openpgp; fpr=E8CB85F76877057A6E27F77AF6B7824F4269A073 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Paolo Abeni commit ce7356ae35943cc6494cc692e62d51a734062b7d upstream. Additional active subflows - i.e. created by the in kernel path manager - are included into the subflow list before starting the 3whs. A racing recvmsg() spooling data received on an already established subflow would unconditionally call tcp_cleanup_rbuf() on all the current subflows, potentially hitting a divide by zero error on the newly created ones. Explicitly check that the subflow is in a suitable state before invoking tcp_cleanup_rbuf(). Fixes: c76c6956566f ("mptcp: call tcp_cleanup_rbuf on subflows") Signed-off-by: Paolo Abeni Reviewed-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/02374660836e1b52afc91966b7535c8c5f7bafb0.173= 1060874.git.pabeni@redhat.com Signed-off-by: Jakub Kicinski [ Conflicts in protocol.c, because commit f410cbea9f3d ("tcp: annotate data-races around tp->window_clamp") has not been backported to this version. The conflict is easy to resolve, because only the context is different, but not the line to modify. ] Signed-off-by: Matthieu Baerts (NGI0) --- net/mptcp/protocol.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 78ac5c538e13..1acd4e37a0ea 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2057,7 +2057,8 @@ static void mptcp_rcv_space_adjust(struct mptcp_sock = *msk, int copied) slow =3D lock_sock_fast(ssk); WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf); tcp_sk(ssk)->window_clamp =3D window_clamp; - tcp_cleanup_rbuf(ssk, 1); + if (tcp_can_send_ack(ssk)) + tcp_cleanup_rbuf(ssk, 1); unlock_sock_fast(ssk, slow); } } --=20 2.45.2