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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 3B8ECC04ABB for ; Tue, 11 Sep 2018 07:04:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D998B206BB for ; Tue, 11 Sep 2018 07:04:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D998B206BB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727616AbeIKMCp (ORCPT ); Tue, 11 Sep 2018 08:02:45 -0400 Received: from mx2.suse.de ([195.135.220.15]:38346 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726455AbeIKMCp (ORCPT ); Tue, 11 Sep 2018 08:02:45 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 0BD2EAEC6; Tue, 11 Sep 2018 07:04:51 +0000 (UTC) From: Juergen Gross To: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, xen-devel@lists.xenproject.org Cc: davem@davemloft.net, boris.ostrovsky@oracle.com, Juergen Gross , stable@vger.kernel.org Subject: [PATCH] xen/netfront: don't bug in case of too many frags Date: Tue, 11 Sep 2018 09:04:48 +0200 Message-Id: <20180911070448.3958-1-jgross@suse.com> X-Mailer: git-send-email 2.16.4 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit 57f230ab04d291 ("xen/netfront: raise max number of slots in xennet_get_responses()") raised the max number of allowed slots by one. This seems to be problematic in some configurations with netback using a larger MAX_SKB_FRAGS value (e.g. old Linux kernel with MAX_SKB_FRAGS defined as 18 instead of nowadays 17). Instead of BUG_ON() in this case just fall back to retransmission. Fixes: 57f230ab04d291 ("xen/netfront: raise max number of slots in xennet_get_responses()") Cc: stable@vger.kernel.org Signed-off-by: Juergen Gross --- drivers/net/xen-netfront.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index 9407acbd19a9..f17f602e6171 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -908,7 +908,11 @@ static RING_IDX xennet_fill_frags(struct netfront_queue *queue, BUG_ON(pull_to <= skb_headlen(skb)); __pskb_pull_tail(skb, pull_to - skb_headlen(skb)); } - BUG_ON(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS); + if (unlikely(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS)) { + queue->rx.rsp_cons = ++cons; + kfree_skb(nskb); + return ~0U; + } skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, skb_frag_page(nfrag), @@ -1045,6 +1049,8 @@ static int xennet_poll(struct napi_struct *napi, int budget) skb->len += rx->status; i = xennet_fill_frags(queue, skb, &tmpq); + if (unlikely(i == ~0U)) + goto err; if (rx->flags & XEN_NETRXF_csum_blank) skb->ip_summed = CHECKSUM_PARTIAL; -- 2.16.4