From patchwork Wed Jul 22 08:57:46 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Wang X-Patchwork-Id: 11677791 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 57969618 for ; Wed, 22 Jul 2020 08:58:54 +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 2D9D520792 for ; Wed, 22 Jul 2020 08:58:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="hMc8pRiy" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2D9D520792 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+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:40376 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jyAaT-0006kP-EF for patchwork-qemu-devel@patchwork.kernel.org; Wed, 22 Jul 2020 04:58:53 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:47970) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jyAa0-0006Jv-1L for qemu-devel@nongnu.org; Wed, 22 Jul 2020 04:58:24 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:50883 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jyAZx-0002PY-NT for qemu-devel@nongnu.org; Wed, 22 Jul 2020 04:58:23 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1595408299; 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=G5iunSP/qQNSr6Ac1EmU9q3Zv828VygEYKpBOU6ZhRM=; b=hMc8pRiyfmetARjQptEz7ywdKoorIOfLTeJWdFmnRukiboXwpYhSelAPdgwEoctWEmPzrj nAeL9cyOEsrkiPBfZF4MwwdWQmRuiHclR2PgNJllOZsy6WRQfBpslb2fMMMUrMX9aXe0Ag TYAZo3WvToUQ+1qJ20LpjTCDPu/+ApU= 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-486-hbF_UoMUNWyDZYPvzZOWyg-1; Wed, 22 Jul 2020 04:58:17 -0400 X-MC-Unique: hbF_UoMUNWyDZYPvzZOWyg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6D8141932481; Wed, 22 Jul 2020 08:58:16 +0000 (UTC) Received: from jason-ThinkPad-X1-Carbon-6th.redhat.com (ovpn-13-156.pek2.redhat.com [10.72.13.156]) by smtp.corp.redhat.com (Postfix) with ESMTP id 006625D9DC; Wed, 22 Jul 2020 08:57:59 +0000 (UTC) From: Jason Wang To: jasowang@redhat.com, qemu-devel@nongnu.org Subject: [PATCH 1/2] net: forbid the reentrant RX Date: Wed, 22 Jul 2020 16:57:46 +0800 Message-Id: <20200722085747.6514-1-jasowang@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=205.139.110.120; envelope-from=jasowang@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/21 23:27:14 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -40 X-Spam_score: -4.1 X-Spam_bar: ---- X-Spam_report: (-4.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, 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=-1, 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: dmitry.fleytman@gmail.com, mst@redhat.com, liq3ea@163.com, liq3ea@gmail.com, alxndr@bu.edu, stefanha@redhat.com, pbonzini@redhat.com Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" The memory API allows DMA into NIC's MMIO area. This means the NIC's RX routine must be reentrant. Instead of auditing all the NIC, we can simply detect the reentrancy and return early. The queue->delivering is set and cleared by qemu_net_queue_deliver() for other queue helpers to know whether the delivering in on going (NIC's receive is being called). We can check it and return early in qemu_net_queue_flush() to forbid reentrant RX. Signed-off-by: Jason Wang --- net/queue.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/queue.c b/net/queue.c index 0164727e39..19e32c80fd 100644 --- a/net/queue.c +++ b/net/queue.c @@ -250,6 +250,9 @@ void qemu_net_queue_purge(NetQueue *queue, NetClientState *from) bool qemu_net_queue_flush(NetQueue *queue) { + if (queue->delivering) + return false; + while (!QTAILQ_EMPTY(&queue->packets)) { NetPacket *packet; int ret;