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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]:52224 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kdDic-00069a-F8 for qemu-devel@archiver.kernel.org; Thu, 12 Nov 2020 09:36:58 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:38174) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kdDhn-0005ho-7S for qemu-devel@nongnu.org; Thu, 12 Nov 2020 09:36:07 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:56896) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kdDhk-0001x9-9Z for qemu-devel@nongnu.org; Thu, 12 Nov 2020 09:36:06 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1605191763; 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: in-reply-to:in-reply-to:references:references; bh=GQ8xrIhKkdj5NghHUebZ1y7g7S0gfxVMmIoOvrjx9CY=; b=JnANrYWRmK3t7Oig9pKSxpHeZ4oqjrSiYZYwqQwV5n9JfD13/eteTBq1aLM7tqkoXt1B5a H70aWSvb2zcZvBkPBPzv8dZO+XuzkYWmPUOz5glmLHPjhUnK/MwcGbYTNEExbOMIFvwwzM IJhXADYnqq9nxth18wxsfVzau1s4Imk= 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-346-FVNBHBHzN6Kh6T2VM3lBtA-1; Thu, 12 Nov 2020 09:35:59 -0500 X-MC-Unique: FVNBHBHzN6Kh6T2VM3lBtA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D41EF1017DD1; Thu, 12 Nov 2020 14:35:57 +0000 (UTC) Received: from work-vm (ovpn-115-60.ams2.redhat.com [10.36.115.60]) by smtp.corp.redhat.com (Postfix) with ESMTPS id DA9571C4; Thu, 12 Nov 2020 14:35:55 +0000 (UTC) Date: Thu, 12 Nov 2020 14:35:48 +0000 From: "Dr. David Alan Gilbert" To: Chuan Zheng Subject: Re: [PATCH] migration/multifd: fix hangup with TLS-Multifd due to blocking handshake Message-ID: <20201112143548.GC13424@work-vm> References: <1604643893-8223-1-git-send-email-zhengchuan@huawei.com> MIME-Version: 1.0 In-Reply-To: <1604643893-8223-1-git-send-email-zhengchuan@huawei.com> User-Agent: Mutt/1.14.6 (2020-07-11) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 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=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=63.128.21.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/11/12 00:52:29 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] 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, 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: yubihong@huawei.com, berrange@redhat.com, zhang.zhanghailiang@huawei.com, quintela@redhat.com, qemu-devel@nongnu.org, xiexiangyou@huawei.com, alex.chen@huawei.com, wanghao232@huawei.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Chuan Zheng (zhengchuan@huawei.com) wrote: > The qemu main loop could hang up forever when we enable TLS+Multifd. > The Src multifd_send_0 invokes tls handshake, it sends hello to sever > and wait response. > However, the Dst main qemu loop has been waiting recvmsg() for multifd_recv_1. > Both of Src and Dst main qemu loop are blocking and waiting for reponse which > results in hanging up forever. > > Src: (multifd_send_0) Dst: (multifd_recv_1) > multifd_channel_connect migration_channel_process_incoming > multifd_tls_channel_connect migration_tls_channel_process_incoming > multifd_tls_channel_connect qio_channel_tls_handshake_task > qio_channel_tls_handshake gnutls_handshake > qio_channel_tls_handshake_task ... > qcrypto_tls_session_handshake ... > gnutls_handshake ... > ... ... > recvmsg (Blocking I/O waiting for response) recvmsg (Blocking I/O waiting for response) > > Fix this by offloadinig handshake work to a background thread. > > Reported-by: Yan Jin > Suggested-by: Daniel P. Berrangé > Signed-off-by: Chuan Zheng Queued > --- > migration/multifd.c | 23 +++++++++++++++++------ > 1 file changed, 17 insertions(+), 6 deletions(-) > > diff --git a/migration/multifd.c b/migration/multifd.c > index 68b171f..88486b9 100644 > --- a/migration/multifd.c > +++ b/migration/multifd.c > @@ -739,6 +739,19 @@ static void multifd_tls_outgoing_handshake(QIOTask *task, > multifd_channel_connect(p, ioc, err); > } > > +static void *multifd_tls_handshake_thread(void *opaque) > +{ > + MultiFDSendParams *p = opaque; > + QIOChannelTLS *tioc = QIO_CHANNEL_TLS(p->c); > + > + qio_channel_tls_handshake(tioc, > + multifd_tls_outgoing_handshake, > + p, > + NULL, > + NULL); > + return NULL; > +} > + > static void multifd_tls_channel_connect(MultiFDSendParams *p, > QIOChannel *ioc, > Error **errp) > @@ -754,12 +767,10 @@ static void multifd_tls_channel_connect(MultiFDSendParams *p, > > trace_multifd_tls_outgoing_handshake_start(ioc, tioc, hostname); > qio_channel_set_name(QIO_CHANNEL(tioc), "multifd-tls-outgoing"); > - qio_channel_tls_handshake(tioc, > - multifd_tls_outgoing_handshake, > - p, > - NULL, > - NULL); > - > + p->c = QIO_CHANNEL(tioc); > + qemu_thread_create(&p->thread, "multifd-tls-handshake-worker", > + multifd_tls_handshake_thread, p, > + QEMU_THREAD_JOINABLE); > } > > static bool multifd_channel_connect(MultiFDSendParams *p, > -- > 1.8.3.1 > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK