From nobody Fri Oct 24 21:49:10 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1518717170011638.7878695294075; Thu, 15 Feb 2018 09:52:50 -0800 (PST) Received: from localhost ([::1]:43703 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1emNiC-00036k-SQ for importer@patchew.org; Thu, 15 Feb 2018 12:52:48 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54015) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1emNgT-00022n-Qr for qemu-devel@nongnu.org; Thu, 15 Feb 2018 12:51:03 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1emNgP-0003KY-2A for qemu-devel@nongnu.org; Thu, 15 Feb 2018 12:51:01 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:60016 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1emNgO-0003Jh-SA for qemu-devel@nongnu.org; Thu, 15 Feb 2018 12:50:56 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 47A314023112; Thu, 15 Feb 2018 17:50:52 +0000 (UTC) Received: from localhost.localdomain.com (unknown [10.42.22.189]) by smtp.corp.redhat.com (Postfix) with ESMTP id 79A212024CAC; Thu, 15 Feb 2018 17:50:51 +0000 (UTC) From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= To: qemu-devel@nongnu.org Date: Thu, 15 Feb 2018 17:50:39 +0000 Message-Id: <20180215175044.8159-3-berrange@redhat.com> In-Reply-To: <20180215175044.8159-1-berrange@redhat.com> References: <20180215175044.8159-1-berrange@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Thu, 15 Feb 2018 17:50:52 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Thu, 15 Feb 2018 17:50:52 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'berrange@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PULL 2/7] io/channel-websock: handle continuous reads without any data X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , Edgar Kaziakhmedov Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" From: Edgar Kaziakhmedov According to the current implementation of websocket protocol in QEMU, qio_channel_websock_handshake_io tries to read handshake from the channel to start communication over socket. But this approach doesn't cover scenario when socket was closed while handshaking. Therefore, if G_IO_IN is caught and qio_channel_read returns zero, error has to be set and connection has to be done. Such behaviour causes 100% CPU load in main QEMU loop, because main loop poll continues to receive and handle G_IO_IN events from websocket. Step to reproduce 100% CPU load: 1) start qemu with the simplest configuration $ qemu -vnc [::1]:1,websocket=3D7500 2) open any vnc listener (which doesn't follow websocket protocol) $ vncviewer :7500 3) kill listener 4) qemu main thread eats 100% CPU Signed-off-by: Edgar Kaziakhmedov Signed-off-by: Daniel P. Berrange --- io/channel-websock.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/io/channel-websock.c b/io/channel-websock.c index 7fd6bb68ba..ec48a305f0 100644 --- a/io/channel-websock.c +++ b/io/channel-websock.c @@ -499,9 +499,12 @@ static int qio_channel_websock_handshake_read(QIOChann= elWebsock *ioc, error_setg(errp, "End of headers not found in first 4096 bytes"); return 1; - } else { - return 0; + } else if (ret =3D=3D 0) { + error_setg(errp, + "End of headers not found before connection closed"= ); + return -1; } + return 0; } *handshake_end =3D '\0'; =20 --=20 2.14.3