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 3D6DCC5AD49 for ; Fri, 6 Jun 2025 13:55:25 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uNXWV-0004Vm-Ph; Fri, 06 Jun 2025 09:54:19 -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 1uNXWT-0004VF-1V for qemu-devel@nongnu.org; Fri, 06 Jun 2025 09:54:17 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uNXWM-0006d3-Ec for qemu-devel@nongnu.org; Fri, 06 Jun 2025 09:54:16 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1749218045; 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=hcQn31tRM4bZxgiO8Fg1CU1z1Neo2FU6ONcj4JrBxd4=; b=Y6XpvTQ/TiPFm/kjxrpfwruawOzWJ5cleVkengadJi//c7xJpilwY83KlbvdruoWprCZFU bfsNrZudebApAHJ3tNfY5vtHJwWhyQC+QWPpGtOK+94h3lxY3Pv1W0/mcgdUvd0Qxy+kQe GC+R9FN09F8aNG5+hXsqGr12PFPn88I= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-144-7d-bDAISPWqs__5_2giQrw-1; Fri, 06 Jun 2025 09:54:04 -0400 X-MC-Unique: 7d-bDAISPWqs__5_2giQrw-1 X-Mimecast-MFC-AGG-ID: 7d-bDAISPWqs__5_2giQrw_1749218043 Received: from mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.15]) (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-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 564AA18002B9; Fri, 6 Jun 2025 13:54:03 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.55]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 23E491956087; Fri, 6 Jun 2025 13:53:59 +0000 (UTC) Date: Fri, 6 Jun 2025 14:53:55 +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 Subject: Re: [PATCH v1] migration: Wait for cpr.sock file to appear before connecting Message-ID: References: <20250605230808.1278840-1-jhkim@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250605230808.1278840-1-jhkim@linux.ibm.com> User-Agent: Mutt/2.2.14 (2025-02-20) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.104, 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 Thu, Jun 05, 2025 at 06:08:08PM -0500, Jaehoon Kim wrote: > When the source VM attempts to connect to the destination VM's Unix > domain socket(cpr.sock) during CPR transfer, the socket file might not > yet be exist if the destination side hasn't completed the bind > operation. This can lead to connection failures when running tests with > the qtest framework. This sounds like a flawed test impl to me - whatever is initiating the cpr operation on the source has done so prematurely - it should ensure the dest is ready before starting the operation. > To address this, add cpr_validate_socket_path(), which wait for the > socket file to appear. This avoids intermittent qtest failures caused by > early connection attempts. IMHO it is dubious to special case cpr in this way. > > Signed-off-by: Jaehoon Kim > Reviewed-by: Jason J. Herne > --- > include/migration/cpr.h | 1 + > migration/cpr-transfer.c | 35 +++++++++++++++++++++++++++++++++++ > 2 files changed, 36 insertions(+) > > diff --git a/include/migration/cpr.h b/include/migration/cpr.h > index 7561fc75ad..cc9384b4f9 100644 > --- a/include/migration/cpr.h > +++ b/include/migration/cpr.h > @@ -23,6 +23,7 @@ MigMode cpr_get_incoming_mode(void); > void cpr_set_incoming_mode(MigMode mode); > bool cpr_is_incoming(void); > > +bool cpr_validate_socket_path(const char *path, Error **errp); > int cpr_state_save(MigrationChannel *channel, Error **errp); > int cpr_state_load(MigrationChannel *channel, Error **errp); > void cpr_state_close(void); > diff --git a/migration/cpr-transfer.c b/migration/cpr-transfer.c > index e1f140359c..3088ed323f 100644 > --- a/migration/cpr-transfer.c > +++ b/migration/cpr-transfer.c > @@ -17,6 +17,33 @@ > #include "migration/vmstate.h" > #include "trace.h" > > +#define CPR_MAX_RETRIES 50 /* Retry for up to 5 seconds */ > +#define CPR_RETRY_DELAY_US 100000 /* 100 ms per retry */ > + > +bool cpr_validate_socket_path(const char *path, Error **errp) > +{ > + struct stat st; > + int retries = CPR_MAX_RETRIES; > + > + do { > + if (!stat(path, &st) && S_ISSOCK(st.st_mode)) { > + return true; > + } > + > + if (errno == ENOENT) { > + usleep(CPR_RETRY_DELAY_US); > + } else { > + error_setg_errno(errp, errno, > + "Unable to check status of socket path '%s'", path); > + return false; > + } > + } while (--retries > 0); > + > + error_setg(errp, "Socket path '%s' not found after %d retries", > + path, CPR_MAX_RETRIES); > + return false; > +} > + > QEMUFile *cpr_transfer_output(MigrationChannel *channel, Error **errp) > { > MigrationAddress *addr = channel->addr; > @@ -28,6 +55,14 @@ QEMUFile *cpr_transfer_output(MigrationChannel *channel, Error **errp) > QIOChannel *ioc = QIO_CHANNEL(sioc); > SocketAddress *saddr = &addr->u.socket; > > + /* > + * Verify that the cpr.sock Unix domain socket file exists and is ready > + * before proceeding with the connection. > + */ > + if (!cpr_validate_socket_path(addr->u.socket.u.q_unix.path, errp)) { > + return NULL; > + } > + > if (qio_channel_socket_connect_sync(sioc, saddr, errp) < 0) { > return NULL; > } > -- > 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 :|