From nobody Fri Dec 27 02:29:42 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 0BEAA1C07F9; Tue, 19 Nov 2024 10:59:14 +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=1732013955; cv=none; b=o/6aB1RXudkcd5sdiN8Gc8p/siwDxQAs5tXB+uoDn2JjmytaUgqp8d6ZbVlVHAABefkd9jNMWqX3QA7q7HbBaOIeMDGt1wAUXUCXfic1hBOUSwVJGa7obrHHpa3vtqjMVRAb7W79Bc6DUXSen848XVIerkIqsn5ZWPWUpjPVevg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732013955; c=relaxed/simple; bh=JVbnu0sAQ/YKJbs+i4PxYwD1ttKgXN1HQFfLAjGEJTw=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=jJuHEv2nhDsnk907uNgOisuSkYmkDhe5Q35FjUr6IPGhPwhHiVqiCXeIB3oP2y0DM0hH2TP1DQnPIkXaINdQsEBmHujBOdrdWYrRUBP18crjXviCKu4owv4QDgyKo3VlxUl1gtvUCNKU42PwiFNRBbQBM/f4d/qrSq5TH69bVIw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=utIUs9p+; 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="utIUs9p+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DBF0DC4CECF; Tue, 19 Nov 2024 10:59:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1732013954; bh=JVbnu0sAQ/YKJbs+i4PxYwD1ttKgXN1HQFfLAjGEJTw=; h=From:To:Cc:Subject:Date:From; b=utIUs9p+rXGG/rUh78inRfp+aX0okAXhuhTfr+UwdOX/dJdWCcdv0dCc/iyhbpgjO z8kTkvunGAEhH3nW6aiNSIzmNSfkcrnx8bhcGu20/8LzQtKiEekKcx5R6JdQYEtHL9 n8Hx27ETAV5jrPe3REQcgaFgpxLEeAIHNEIbtSXxvhtyycl7NsLCuz24n3XFkl6Ljq qu2+/QJsNqCSebXIZtzGwCCpWMjV8/dFgMngdFAE0d+MkT4Bi14CLBBHf6S7oHTZaU gq1/J7DwsrlnJl77EMDwLQvQA4KqrTEqGfwpjPJ/Zr31IfBYC9XmNUGknDzztgrpk1 ej20xfsoSlw+g== 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 5.15.y] mptcp: cope racing subflow creation in mptcp_rcv_space_adjust Date: Tue, 19 Nov 2024 11:58:59 +0100 Message-ID: <20241119105858.3494900-2-matttbe@kernel.org> X-Mailer: git-send-email 2.45.2 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=K/yzLVBVKv8VyVxf+d0AlQvJI8/Ma/Ji3Y7ZjJX2y6Q=; b=owEBbQKS/ZANAwAIAfa3gk9CaaBzAcsmYgBnPG9yRcu4JBlHcEyzPkuKKJtWdaZFEoTfZX+P2 1WXLwkVceSJAjMEAAEIAB0WIQToy4X3aHcFem4n93r2t4JPQmmgcwUCZzxvcgAKCRD2t4JPQmmg c0k0EADpQwFeGh7AF8tm6wE7KgOxOqTgWw9bHKcG40r9l/hz0JkHlFc508PQfqWkpkSr24dTa8q ItlT+W7V7m15Va9OCz8V6Ko5GAacO2yUOtl5E91WYvtn6Xi6ZIYFdYv0nSTUO/00X0tbOi5Oaly SkwgFXCx41FN4XBtk5x84tORqwuJhPu0TLSwIT6+GDegrPA8xDDbRmwEw8rwY+USwn0zDZKFaL6 8VND8gbVMl2HUXywG6Dgr7NDhdlhTwJ6luidaKpHoQz1gHXA/KlsfcM86lFYH+t6OlVhWbvv4w3 9bT9dY6ADsfazrtp5DkFUVYEU2KKCtHIpQHxRcguxn8kgVFXMsi82EPyEiaYXyEKxXrWI135pY5 1fgj0o378zAOsJdyXyblrc20bLTDyhrCOtsxmy4MoBAOKgfI0p6lj4r+TXspzhIzGnWnpaAG5EH Aw5Lm1SnAH/OAhwbI3awByJrS3CkM9kXgPpoVN+XgZv0VE8khtk1mEkt+Y2gmB+DZUEDDqQtNdB 028dfyif6Cx5PEDIVabqgSpPTXhihc1tQoeFzc1TG63J0JeagHC/C3XEcPEl4VXkwAA7UPiuKBw jeNo4wkzTTQCUYtYsnQm67fjJfpp7MAlGbLGvhlHlf5wRKfE8oqQEkxvsLOj01KEUa0DexsFRaZ Z9ap7S58MAAAKBg== 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 34c98596350e..bcbb1f92ce24 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1986,7 +1986,8 @@ 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