From patchwork Tue Jul 28 05:57:58 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Wang X-Patchwork-Id: 277356 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 52D44C433E3 for ; Tue, 28 Jul 2020 05:59:21 +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 1E55320658 for ; Tue, 28 Jul 2020 05:59:21 +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="O6a82oKF" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1E55320658 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]:46944 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1k0Ie0-0002lv-Dw for qemu-devel@archiver.kernel.org; Tue, 28 Jul 2020 01:59:20 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45618) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1k0Id3-0001Sv-I3 for qemu-devel@nongnu.org; Tue, 28 Jul 2020 01:58:21 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:38614 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 1k0Id1-0007Bg-W2 for qemu-devel@nongnu.org; Tue, 28 Jul 2020 01:58:21 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1595915899; 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=O6a82oKFwGMeEhCRzI4wI+bfYB49kfxgRGeiCbA2LIHYJ1eOxZcV0eqX6gjaavqFIGC9U+ 81lM4JqssiWH0L89JGPmkna26JPTvzbLZXHDGNm1AmLiySAwnikFTqel8q53puPHclyp54 hFR951Uibl6ITiJ/X3yBcaZ6BU0BjJI= 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-101-rG0HKfY3Psqa8S7ykjuuww-1; Tue, 28 Jul 2020 01:58:15 -0400 X-MC-Unique: rG0HKfY3Psqa8S7ykjuuww-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 73A091005504; Tue, 28 Jul 2020 05:58:14 +0000 (UTC) Received: from jason-ThinkPad-T430s.redhat.com (ovpn-13-130.pek2.redhat.com [10.72.13.130]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1BA021002388; Tue, 28 Jul 2020 05:58:12 +0000 (UTC) From: Jason Wang To: peter.maydell@linaro.org Subject: [PULL 4/4] net: forbid the reentrant RX Date: Tue, 28 Jul 2020 13:57:58 +0800 Message-Id: <1595915878-22568-5-git-send-email-jasowang@redhat.com> In-Reply-To: <1595915878-22568-1-git-send-email-jasowang@redhat.com> References: <1595915878-22568-1-git-send-email-jasowang@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=jasowang@redhat.com 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;