From mboxrd@z Thu Jan 1 00:00:00 1970 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=-10.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 AA564C43387 for ; Fri, 11 Jan 2019 14:17:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7A6DD21841 for ; Fri, 11 Jan 2019 14:17:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547216249; bh=6H3ujWPjbVHbrG2+00y2M2QkEO+p86mu9x1SfKhpCqo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Q/9+TkWtH7MXl40pQezq9c6o7K9EDnWrBkZICyaZkvOv6NP4i75wChCx4uIaaUavq zNRbS8ds7hhY4Kxvwa0dx3uvjEBx55O7NjypAM5eP2TqYyZ2rfD1KKxJFAxste2aZS 0R8uzmfs0e+dFekx6g6TxZqanlpf5TyehYQkdMLk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731921AbfAKOR2 (ORCPT ); Fri, 11 Jan 2019 09:17:28 -0500 Received: from mail.kernel.org ([198.145.29.99]:33806 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729564AbfAKORY (ORCPT ); Fri, 11 Jan 2019 09:17:24 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id F075D2177B; Fri, 11 Jan 2019 14:17:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547216243; bh=6H3ujWPjbVHbrG2+00y2M2QkEO+p86mu9x1SfKhpCqo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Vcx7ZY6Sn9tIP8ZZROnuCzYyKGKkqdYeXdLRmKX1iZmsaYavD0jKEIzDLGxk71NIc Mw6+l/pinLKEGxhfSSAAq1GgSbRBvxXOFKhoqPlJgvjUIWx7OGgr3yBG6NaWA5/kU6 CBfhagskgscxbjpg+Q7uaRZ/viPTX8IeSlRg2W7Y= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dietmar Hahn , Juergen Gross , "David S. Miller" Subject: [PATCH 4.4 27/88] xen/netfront: tolerate frags with no data Date: Fri, 11 Jan 2019 15:07:56 +0100 Message-Id: <20190111131050.132215217@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190111131045.137499039@linuxfoundation.org> References: <20190111131045.137499039@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Juergen Gross [ Upstream commit d81c5054a5d1d4999c7cdead7636b6cd4af83d36 ] At least old Xen net backends seem to send frags with no real data sometimes. In case such a fragment happens to occur with the frag limit already reached the frontend will BUG currently even if this situation is easily recoverable. Modify the BUG_ON() condition accordingly. Tested-by: Dietmar Hahn Signed-off-by: Juergen Gross Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/xen-netfront.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -889,7 +889,7 @@ static RING_IDX xennet_fill_frags(struct if (skb_shinfo(skb)->nr_frags == MAX_SKB_FRAGS) { unsigned int pull_to = NETFRONT_SKB_CB(skb)->pull_to; - BUG_ON(pull_to <= skb_headlen(skb)); + BUG_ON(pull_to < skb_headlen(skb)); __pskb_pull_tail(skb, pull_to - skb_headlen(skb)); } if (unlikely(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS)) {