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 X-Spam-Level: X-Spam-Status: No, score=-15.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C4642C49EA6 for ; Thu, 24 Jun 2021 17:21:23 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 7C7BE613EA for ; Thu, 24 Jun 2021 17:21:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7C7BE613EA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:59960 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lwT2Y-0005Z5-B4 for qemu-devel@archiver.kernel.org; Thu, 24 Jun 2021 13:21:22 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:41152) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lwT1h-0004ne-A5 for qemu-devel@nongnu.org; Thu, 24 Jun 2021 13:20:29 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:44021) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lwT1c-0007hh-Nv for qemu-devel@nongnu.org; Thu, 24 Jun 2021 13:20:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1624555223; 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: in-reply-to:in-reply-to:references:references; bh=lP0loLMZ6n5vn1BY/xE6nm3wnPOKqHmnDp78EhgPL+Y=; b=P8cXkGR/5lkx6l+N+/ik8B7XJVmsyE00bHuCrtfSDPF6XfQrDcnKL0nSW+sDOjrAkkrknx v4hZ/0GH78oGTcGuKwHLM9lrkVnWkMH5dU0wWso8rq7bWp7XqYyMmhAgClK29Xqdo6bFfb vyRjcNVk8ddZsz+9vZ76mRArCDCyYro= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-213-Swxz8pa2PO-WkZ9O9Dj3KA-1; Thu, 24 Jun 2021 13:20:20 -0400 X-MC-Unique: Swxz8pa2PO-WkZ9O9Dj3KA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 19E661835AC5; Thu, 24 Jun 2021 17:20:19 +0000 (UTC) Received: from work-vm (ovpn-114-255.ams2.redhat.com [10.36.114.255]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 907E65D6AB; Thu, 24 Jun 2021 17:20:11 +0000 (UTC) Date: Thu, 24 Jun 2021 18:20:08 +0100 From: "Dr. David Alan Gilbert" To: Leonardo Bras Subject: Re: [PATCH v1 1/1] migration: Unregister yank if migration setup fails Message-ID: References: <20210622024236.600347-1-leobras@redhat.com> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/2.0.7 (2021-05-04) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 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; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=216.205.24.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.362, 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 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Lukas Straub , qemu-devel@nongnu.org, Peter Xu , Juan Quintela Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Dr. David Alan Gilbert (dgilbert@redhat.com) wrote: > * Leonardo Bras (leobras@redhat.com) wrote: > > Currently, if a qemu instance is started with "-incoming defer" and > > an incorect parameter is passed to "migrate_incoming", it will print the > > expected error and reply with "duplicate yank instance" for any upcoming > > "migrate_incoming" command. > > > > This renders current qemu process unusable, and requires a new qemu > > process to be started before accepting a migration. > > > > This is caused by a yank_register_instance() that happens in > > qemu_start_incoming_migration() but is never reverted if any error > > happens. > > > > Solves this by unregistering the instance if anything goes wrong > > in the function, allowing a new "migrate_incoming" command to be > > accepted. > > > > Fixes: b5eea99ec2f ("migration: Add yank feature", 2021-01-13) > > Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1974366 > > Signed-off-by: Leonardo Bras > > > > --- > > migration/migration.c | 6 +++++- > > 1 file changed, 5 insertions(+), 1 deletion(-) > > > > diff --git a/migration/migration.c b/migration/migration.c > > index 4228635d18..ddcf9e1868 100644 > > --- a/migration/migration.c > > +++ b/migration/migration.c > > @@ -474,9 +474,13 @@ static void qemu_start_incoming_migration(const char *uri, Error **errp) > > } else if (strstart(uri, "fd:", &p)) { > > fd_start_incoming_migration(p, errp); > > } else { > > - yank_unregister_instance(MIGRATION_YANK_INSTANCE); > > error_setg(errp, "unknown migration protocol: %s", uri); > > } > > + > > + if (*errp) { > > + yank_unregister_instance(MIGRATION_YANK_INSTANCE); > > + } > > My understanding is that testing *errp isn't allowed, because > it's legal to pass NULL to ignore errors, or legal to pass > &error_abort to mean that any error you do hit will cause the > process to assert; so you need to have something separate you can test. Ah, and armbru points out there's a 'new' mechanism to make it safe; you need to use ERRP_GUARD, see include/qapi/error.h if you want to be able to test it. Dave > Dave > > > } > > > > static void process_incoming_migration_bh(void *opaque) > > -- > > 2.32.0 > > > -- > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK