From patchwork Thu Mar 27 12:56:13 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Durrant X-Patchwork-Id: 334327 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id A1CE71400E2 for ; Thu, 27 Mar 2014 23:56:47 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756597AbaC0M4o (ORCPT ); Thu, 27 Mar 2014 08:56:44 -0400 Received: from smtp.citrix.com ([66.165.176.89]:39776 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753946AbaC0M4d (ORCPT ); Thu, 27 Mar 2014 08:56:33 -0400 X-IronPort-AV: E=Sophos;i="4.97,742,1389744000"; d="scan'208";a="115424511" Received: from accessns.citrite.net (HELO FTLPEX01CL03.citrite.net) ([10.9.154.239]) by FTLPIPO01.CITRIX.COM with ESMTP; 27 Mar 2014 12:56:21 +0000 Received: from ukmail1.uk.xensource.com (10.80.16.128) by smtprelay.citrix.com (10.13.107.80) with Microsoft SMTP Server id 14.2.342.4; Thu, 27 Mar 2014 08:56:19 -0400 Received: from etemp.uk.xensource.com ([10.80.228.66] helo=etemp.uk.xensource.com.) by ukmail1.uk.xensource.com with esmtp (Exim 4.69) (envelope-from ) id 1WT9r1-0002ms-N3; Thu, 27 Mar 2014 12:56:19 +0000 From: Paul Durrant To: , CC: Paul Durrant , Ian Campbell , Wei Liu , Sander Eikelenboom Subject: [PATCH net v2 3/3] xen-netback: BUG_ON in xenvif_rx_action() not catching overflow Date: Thu, 27 Mar 2014 12:56:13 +0000 Message-ID: <1395924973-42904-4-git-send-email-paul.durrant@citrix.com> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1395924973-42904-1-git-send-email-paul.durrant@citrix.com> References: <1395924973-42904-1-git-send-email-paul.durrant@citrix.com> MIME-Version: 1.0 X-DLP: MIA1 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The BUG_ON to catch ring overflow in xenvif_rx_action() makes the assumption that meta_slots_used == ring slots used. This is not necessarily the case for GSO packets, because the non-prefix GSO protocol consumes one more ring slot than meta-slot for the 'extra_info'. This patch changes the test to actually check ring slots. Signed-off-by: Paul Durrant Cc: Ian Campbell Cc: Wei Liu Cc: Sander Eikelenboom --- v2: - Add explanation as to why meta_slots_used != ring slots used drivers/net/xen-netback/netback.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index aa87ae8..cbe6d6a 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -482,6 +482,8 @@ static void xenvif_rx_action(struct xenvif *vif) while ((skb = skb_dequeue(&vif->rx_queue)) != NULL) { RING_IDX max_slots_needed; + RING_IDX old_req_cons; + RING_IDX ring_slots_used; int i; /* We need a cheap worse case estimate for the number of @@ -521,8 +523,12 @@ static void xenvif_rx_action(struct xenvif *vif) vif->rx_last_skb_slots = 0; sco = (struct skb_cb_overlay *)skb->cb; + + old_req_cons = vif->rx.req_cons; sco->meta_slots_used = xenvif_gop_skb(skb, &npo); - BUG_ON(sco->meta_slots_used > max_slots_needed); + ring_slots_used = vif->rx.req_cons - old_req_cons; + + BUG_ON(ring_slots_used > max_slots_needed); __skb_queue_tail(&rxq, skb); }