From patchwork Wed Feb 28 05:12:56 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 13574880 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 7FA55C47DD9 for ; Wed, 28 Feb 2024 05:17:45 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rfCHJ-0006cd-2c; Wed, 28 Feb 2024 00:14:49 -0500 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 1rfCHH-0006YB-A0 for qemu-devel@nongnu.org; Wed, 28 Feb 2024 00:14:47 -0500 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 1rfCH1-0006cI-5y for qemu-devel@nongnu.org; Wed, 28 Feb 2024 00:14:42 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1709097264; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=wExLy3AKx0EGsAonwI9YK2ZuyIYTZqi6zUyh5A8Ohtw=; b=iux2E/7KsCxwYKtONyxPYxBnVLv9FY0DecJVPSDBYWTi3E1qCTUbA0DS8ppOQ4dgXfUFVj 1vWw3VovSDvKjY8D+D//gUoU/3bZ9bWJSBaGdRmeqgwPp/PkkOeGjRk7Sor+bqW3y0d5aU 2OC5V0KdfDmn6x0qxu9oZGv7ODyGaVA= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-689-9nZywqdrNHyX6BveCwyZJw-1; Wed, 28 Feb 2024 00:14:21 -0500 X-MC-Unique: 9nZywqdrNHyX6BveCwyZJw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (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 mimecast-mx02.redhat.com (Postfix) with ESMTPS id 754A0800074; Wed, 28 Feb 2024 05:14:21 +0000 (UTC) Received: from x1n.redhat.com (unknown [10.72.116.12]) by smtp.corp.redhat.com (Postfix) with ESMTP id 291541C060AF; Wed, 28 Feb 2024 05:14:12 +0000 (UTC) From: peterx@redhat.com To: Peter Maydell , qemu-devel@nongnu.org Cc: David Hildenbrand , Eric Blake , Laurent Vivier , Paolo Bonzini , =?utf-8?q?C=C3=A9dric_Le_Goater?= , Gerd Hoffmann , =?utf-8?q?Marc-Andr=C3=A9_Lureau?= , Markus Armbruster , Fabiano Rosas , "Michael S. Tsirkin" , Thomas Huth , Jason Wang , Alex Williamson , Peter Xu Subject: [PULL 06/25] migration/multifd: Cleanup TLS iochannel referencing Date: Wed, 28 Feb 2024 13:12:56 +0800 Message-ID: <20240228051315.400759-7-peterx@redhat.com> In-Reply-To: <20240228051315.400759-1-peterx@redhat.com> References: <20240228051315.400759-1-peterx@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.7 Received-SPF: pass client-ip=170.10.129.124; envelope-from=peterx@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=-0.088, 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_H2=-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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Peter Xu Commit a1af605bd5 ("migration/multifd: fix hangup with TLS-Multifd due to blocking handshake") introduced a thread for TLS channels, which will resolve the issue on blocking the main thread. However in the same commit p->c is slightly abused just to be able to pass over the pointer "p" into the thread. That's the major reason we'll need to conditionally free the io channel in the fault paths. To clean it up, using a separate structure to pass over both "p" and "tioc" in the tls handshake thread. Then we can make it a rule that p->c will never be set until the channel is completely setup. With that, we can drop the tricky conditional unref of the io channel in the error path. Reviewed-by: Fabiano Rosas Link: https://lore.kernel.org/r/20240222095301.171137-2-peterx@redhat.com Signed-off-by: Peter Xu --- migration/multifd.c | 37 +++++++++++++++++++++++-------------- 1 file changed, 23 insertions(+), 14 deletions(-) diff --git a/migration/multifd.c b/migration/multifd.c index 43f0820996..84a6b9e58f 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -891,16 +891,22 @@ out: static void multifd_new_send_channel_async(QIOTask *task, gpointer opaque); +typedef struct { + MultiFDSendParams *p; + QIOChannelTLS *tioc; +} MultiFDTLSThreadArgs; + static void *multifd_tls_handshake_thread(void *opaque) { - MultiFDSendParams *p = opaque; - QIOChannelTLS *tioc = QIO_CHANNEL_TLS(p->c); + MultiFDTLSThreadArgs *args = opaque; - qio_channel_tls_handshake(tioc, + qio_channel_tls_handshake(args->tioc, multifd_new_send_channel_async, - p, + args->p, NULL, NULL); + g_free(args); + return NULL; } @@ -910,6 +916,7 @@ static bool multifd_tls_channel_connect(MultiFDSendParams *p, { MigrationState *s = migrate_get_current(); const char *hostname = s->hostname; + MultiFDTLSThreadArgs *args; QIOChannelTLS *tioc; tioc = migration_tls_client_create(ioc, hostname, errp); @@ -924,11 +931,14 @@ static bool multifd_tls_channel_connect(MultiFDSendParams *p, object_unref(OBJECT(ioc)); trace_multifd_tls_outgoing_handshake_start(ioc, tioc, hostname); qio_channel_set_name(QIO_CHANNEL(tioc), "multifd-tls-outgoing"); - p->c = QIO_CHANNEL(tioc); + + args = g_new0(MultiFDTLSThreadArgs, 1); + args->tioc = tioc; + args->p = p; p->tls_thread_created = true; qemu_thread_create(&p->tls_thread, "multifd-tls-handshake-worker", - multifd_tls_handshake_thread, p, + multifd_tls_handshake_thread, args, QEMU_THREAD_JOINABLE); return true; } @@ -941,6 +951,7 @@ static bool multifd_channel_connect(MultiFDSendParams *p, migration_ioc_register_yank(ioc); p->registered_yank = true; + /* Setup p->c only if the channel is completely setup */ p->c = ioc; p->thread_created = true; @@ -994,14 +1005,12 @@ out: trace_multifd_new_send_channel_async_error(p->id, local_err); multifd_send_set_error(local_err); - if (!p->c) { - /* - * If no channel has been created, drop the initial - * reference. Otherwise cleanup happens at - * multifd_send_channel_destroy() - */ - object_unref(OBJECT(ioc)); - } + /* + * For error cases (TLS or non-TLS), IO channel is always freed here + * rather than when cleanup multifd: since p->c is not set, multifd + * cleanup code doesn't even know its existence. + */ + object_unref(OBJECT(ioc)); error_free(local_err); }