From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 41AC3C677C4 for ; Tue, 10 Jun 2025 17:09:42 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uP2TR-0000yw-Pc; Tue, 10 Jun 2025 13:09:21 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uP2TP-0000yS-Qy for qemu-devel@nongnu.org; Tue, 10 Jun 2025 13:09:19 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uP2TN-0005mH-Iw for qemu-devel@nongnu.org; Tue, 10 Jun 2025 13:09:19 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1749575356; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=QJ7wO+3yOGVnpnCn3mB53ROGNUHE+f/tQZm7nXCX5fM=; b=hesQDKeKZLElfLjgzyfRdqIgQvZ36Q/eN9XbiP4NSH4XdQfH3ehaTNtbH7bpw5ksNrLsXG TywfwT5pbJw5+jSIArA5WyWRb7g+7La72cYX1oknLw8QXDM3a1P527zQCusMFIrAJM/sLg Xx5Z0ciubZEytB7/4jKblxGCx0WiLCs= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-471-hpKtuTELObq6vhi7Cd7v-Q-1; Tue, 10 Jun 2025 13:09:12 -0400 X-MC-Unique: hpKtuTELObq6vhi7Cd7v-Q-1 X-Mimecast-MFC-AGG-ID: hpKtuTELObq6vhi7Cd7v-Q_1749575351 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 554E819560B6; Tue, 10 Jun 2025 17:09:11 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.87]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id CE52530001B1; Tue, 10 Jun 2025 17:09:07 +0000 (UTC) Date: Tue, 10 Jun 2025 18:09:04 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Jaehoon Kim Cc: qemu-devel@nongnu.org, jjherne@linux.ibm.com, steven.sistare@oracle.com, peterx@redhat.com, farosas@suse.de, lvivier@redhat.com, pbonzini@redhat.com Subject: Re: [PATCH v2] migration: Setup pre-listened cpr.sock to remove race-condition. Message-ID: References: <20250610150849.326194-1-jhkim@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250610150849.326194-1-jhkim@linux.ibm.com> User-Agent: Mutt/2.2.14 (2025-02-20) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Tue, Jun 10, 2025 at 10:08:49AM -0500, Jaehoon Kim wrote: > When the source VM attempts to connect to the destination VM's Unix > domain socket (cpr.sock) during a cpr-transfer test, race conditions can > occur if the socket file isn't ready. This can lead to connection > failures when running tests. > > This patch creates and listens on the socket in advance, and passes the > pre-listened FD directly. This avoids timing issues and improves the > reliability of CPR tests. > > Reviewed-by: Jason J. Herne > Signed-off-by: Jaehoon Kim > > --- > Changes since v1: > - In v1, the patch added a wait loop to poll the existence of the socket > file (cpr_validate_socket_path()). > > - This version instead creates the socket beforehand and passes its FD > to the destination QEMU, eliminating the race condition entirely. > > - Commit title and message changed accordingly. > --- > migration/cpr-transfer.c | 3 +- > tests/qtest/migration/cpr-tests.c | 72 ++++++++++++++++++++++++++++++- > 2 files changed, 72 insertions(+), 3 deletions(-) > diff --git a/tests/qtest/migration/cpr-tests.c b/tests/qtest/migration/cpr-tests.c > index 5536e14610..6f90160e21 100644 > --- a/tests/qtest/migration/cpr-tests.c > +++ b/tests/qtest/migration/cpr-tests.c > @@ -50,6 +50,51 @@ static void *test_mode_transfer_start(QTestState *from, QTestState *to) > return NULL; > } > > +/* > + * Create a pre-listened UNIX domain socket at the specified path. > + * > + * This is used to eliminate a race condition that can occur > + * intermittently in qtest during CPR tests. By pre-creating and > + * listening on the socket, we avoid timing-related issues. > + */ > +static int setup_socket_listener(const char *path) > +{ > + struct sockaddr_un un; > + size_t pathlen; > + int sock_fd; > + > + sock_fd = socket(PF_UNIX, SOCK_STREAM, 0); > + if (sock_fd < 0) { > + g_test_message("Failed to create Unix socket"); > + return -1; > + } > + > + pathlen = strlen(path); > + if (pathlen >= sizeof(un.sun_path)) { > + g_test_message("UNIX socket path '%s' is too long", path); > + close(sock_fd); > + return -1; > + } > + > + memset(&un, 0, sizeof(un)); > + un.sun_family = AF_UNIX; > + strncpy(un.sun_path, path, sizeof(un.sun_path) - 1); > + > + if (bind(sock_fd, (struct sockaddr *)&un, sizeof(un)) < 0) { > + g_test_message("Failed to bind socket to %s", path); > + close(sock_fd); > + return -1; > + } > + > + if (listen(sock_fd, 1) < 0) { > + g_test_message("Failed to listen on socket %s", path); > + close(sock_fd); > + return -1; > + } > + > + return sock_fd; > +} This is effectively re-implementing 'unix_listen', so just use that function. > @@ -75,6 +120,29 @@ static void test_mode_transfer_common(bool incoming_defer) > " 'path': '%s' } } ]", > mig_path); > > + /* > + * Determine socket address type and value. > + * If socket creation fails, provide the socket path to the target, > + * so it can create the Unix domain socket itself. > + * Otherwise, use the pre-listened socket file descriptor directly. > + */ > + int cpr_sockfd = setup_socket_listener(cpr_path); > + > + if (cpr_sockfd < 0) { A failure of this function (or in future 'unix_listen') shouldn't trigger any fallback logic - we should report it and fail thue test. > + addr_type = g_strdup("unix"); > + addr_key = g_strdup("path"); > + addr_value = g_strdup(cpr_path); > + } else { > + addr_type = g_strdup("fd"); > + addr_key = g_strdup("str"); > + addr_value = g_strdup_printf("%d", cpr_sockfd); > + } > + > + opts_target = g_strdup_printf("-incoming cpr,addr.transport=socket," > + "addr.type=%s,addr.%s=%s %s", > + addr_type, addr_key, addr_value, opts); > + > + > MigrateCommon args = { > .start.opts_source = opts, > .start.opts_target = opts_target, > -- > 2.49.0 > > With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|