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 00763C433F5 for ; Wed, 13 Apr 2022 11:35:04 +0000 (UTC) Received: from localhost ([::1]:59690 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nebH5-0003BJ-Tq for qemu-devel@archiver.kernel.org; Wed, 13 Apr 2022 07:35:03 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45164) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nebFk-0002UM-I3 for qemu-devel@nongnu.org; Wed, 13 Apr 2022 07:33:42 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:34375) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nebFh-0002iR-VU for qemu-devel@nongnu.org; Wed, 13 Apr 2022 07:33:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1649849616; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=4TaEgiUn5QrpLauDqLHQ5RbLCk/wBYK6Ok5lmEEY470=; b=Sk+j5+O4twcX/Dzx2WIsUmIj+v+nyrsOrtGmsKnGkt5DJRyEsj7F1JCqzU7Zzfvjh7EgJM G1WMAMlY2VwkvLjCwMqaYJTr1KRLs7AjAlrk9K03HuGPQ569XpvLpRpI4YKtGodhuXves4 mm6BzrKJj5OAJxYP7osvNdNJOvJxwUU= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-467-lPSWXmdXNH-SlU_75WiRqg-1; Wed, 13 Apr 2022 07:33:35 -0400 X-MC-Unique: lPSWXmdXNH-SlU_75WiRqg-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 82075802803 for ; Wed, 13 Apr 2022 11:33:35 +0000 (UTC) Received: from dgilbert-t580.localhost (unknown [10.39.192.19]) by smtp.corp.redhat.com (Postfix) with ESMTP id 939744229B9; Wed, 13 Apr 2022 11:33:34 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, quintela@redhat.com, peterx@redhat.com, leobras@redhat.com Subject: [PATCH] migration: Read state once Date: Wed, 13 Apr 2022 12:33:29 +0100 Message-Id: <20220413113329.103696-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.85 on 10.11.54.9 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dgilbert@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-type: text/plain Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.129.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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: , Cc: pkrempa@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: "Dr. David Alan Gilbert" The 'status' field for the migration is updated normally using an atomic operation from the migration thread. Most readers of it aren't that careful, and in most cases it doesn't matter. In query_migrate->fill_source_migration_info the 'state' is read twice; the first time to decide which state fields to fill in, and then secondly to copy the state to the status field; that can end up with a status that's inconsistent; e.g. setting up the fields for 'setup' and then having an 'active' status. In that case libvirt gets upset by the lack of ram info. The symptom is: libvirt.libvirtError: internal error: migration was active, but no RAM info was set Read the state exactly once in fill_source_migration_info. This is a possible fix for: https://bugzilla.redhat.com/show_bug.cgi?id=2074205 Signed-off-by: Dr. David Alan Gilbert --- migration/migration.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/migration/migration.c b/migration/migration.c index 695f0f2900..811c584619 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -1073,6 +1073,7 @@ static void populate_disk_info(MigrationInfo *info) static void fill_source_migration_info(MigrationInfo *info) { MigrationState *s = migrate_get_current(); + int state = qatomic_read(&s->state); GSList *cur_blocker = migration_blockers; info->blocked_reasons = NULL; @@ -1092,7 +1093,7 @@ static void fill_source_migration_info(MigrationInfo *info) } info->has_blocked_reasons = info->blocked_reasons != NULL; - switch (s->state) { + switch (state) { case MIGRATION_STATUS_NONE: /* no migration has happened ever */ /* do not overwrite destination migration status */ @@ -1137,7 +1138,7 @@ static void fill_source_migration_info(MigrationInfo *info) info->has_status = true; break; } - info->status = s->state; + info->status = state; } typedef enum WriteTrackingSupport { -- 2.35.1