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=-10.6 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=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 A1D5AC43612 for ; Mon, 7 Jan 2019 13:07:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6932F2089F for ; Mon, 7 Jan 2019 13:07:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1546866474; bh=S6z9Hmr8PNVA9OadlFnQbAcYOXeIo6U9pAGffWFPQpI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=VhwddigTyUgsyYymDBu1f/SUgoDqMTmJJ3r8VgciRIS/ubsnVEbs6LnNd2zQ2HSRC v1TQRWi/UJw5JiEt0/CYfPcRQ74UsqSgPJuOT4Iovnz0iG1MyWgO4ZG3s/fBDDLN3O H5VnRntI793ckm5WtwcLi3aDe0HvaMM3rMxkn40M= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730027AbfAGNHi (ORCPT ); Mon, 7 Jan 2019 08:07:38 -0500 Received: from mail.kernel.org ([198.145.29.99]:54686 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731131AbfAGNHh (ORCPT ); Mon, 7 Jan 2019 08:07:37 -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 975972147C; Mon, 7 Jan 2019 13:07:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1546866456; bh=S6z9Hmr8PNVA9OadlFnQbAcYOXeIo6U9pAGffWFPQpI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ql+hHYA4e34AvIaW8Cdbe9IKAL/jkGtAR//+yv/ItNaqEpacKUCsnzz4l+WQDGX9n uWFChALOzQSh92GfrazENtQMzYvn36p9eG9X2uvn2wJZnbwSw8dhONTIwopUze6A3y m38nbgxgiqtFZzrKleArC/XOJIdGu2KXUVNI55bE= 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 4.9 22/71] xen/netfront: tolerate frags with no data Date: Mon, 7 Jan 2019 13:32:51 +0100 Message-Id: <20190107105334.074271771@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190107105330.280153213@linuxfoundation.org> References: <20190107105330.280153213@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: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.9-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 @@ -903,7 +903,7 @@ 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)) {