From patchwork Tue Jul 28 09:10:19 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Wang X-Patchwork-Id: 277333 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=-9.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS autolearn=unavailable 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 70AAFC433DF for ; Tue, 28 Jul 2020 09:12:59 +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 39E7920759 for ; Tue, 28 Jul 2020 09:12:59 +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="NNfq+3tD" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 39E7920759 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]:54968 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1k0LfO-0000sW-IV for qemu-devel@archiver.kernel.org; Tue, 28 Jul 2020 05:12:58 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:60034) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1k0Ld9-0006Ok-RR for qemu-devel@nongnu.org; Tue, 28 Jul 2020 05:10:39 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:39093 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 1k0Ld8-0007Df-9g for qemu-devel@nongnu.org; Tue, 28 Jul 2020 05:10:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1595927437; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:content-type:content-type:in-reply-to:in-reply-to: references:references; bh=BizKAjSDHwqLVrq96cuiIXoDoNkf2Pbi3L5JlP/JAHo=; b=NNfq+3tDlUgum+tX/fc4QPR30/gtTOAuRdzW9Zhj5R6mh2B1LpcJIKwypPTZrybl5LRahZ dZ5yoNM6EqdHt4L0JnkMVcfThZMW1cEO32dmiGQ9uJFLNk9jNdqJuXx1KJQbf9ewl9kO4i zoAdVHPtVxMQ/rSE3KcziAfE3m3MKi0= 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-481-jK5oLramPnaKBWu5pCTfiQ-1; Tue, 28 Jul 2020 05:10:35 -0400 X-MC-Unique: jK5oLramPnaKBWu5pCTfiQ-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 E26E51932480; Tue, 28 Jul 2020 09:10:34 +0000 (UTC) Received: from jason-ThinkPad-T430s.redhat.com (ovpn-12-214.pek2.redhat.com [10.72.12.214]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6F7EE90E62; Tue, 28 Jul 2020 09:10:33 +0000 (UTC) From: Jason Wang To: peter.maydell@linaro.org Subject: [PULL V2 3/3] net: forbid the reentrant RX Date: Tue, 28 Jul 2020 17:10:19 +0800 Message-Id: <1595927419-27346-4-git-send-email-jasowang@redhat.com> In-Reply-To: <1595927419-27346-1-git-send-email-jasowang@redhat.com> References: <1595927419-27346-1-git-send-email-jasowang@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=207.211.31.120; envelope-from=jasowang@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/27 23:55:28 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 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_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, 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: Jason Wang , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.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 0164727..19e32c8 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;