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=-9.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,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 AF003C43444 for ; Wed, 26 Dec 2018 22:58:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 731952070B for ; Wed, 26 Dec 2018 22:58:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1545865085; bh=7rdMI+vpU5BXSaOm7tktjFG9kot4nRrYIaXL9lL/GPo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ExmrnO2lh2Dx36iwFHZ+GzUiqU/t/ZRNj8glS6Ilu49G+7ZumFI64B442zBLyXBQK JPkCJfHIDJO3af9nNeb9NEffc0X+brxRQ46YDz6fHDNmPbKPWR/JOp3w9R/ZxMsjZh cOXe/tGZhGzFS3CQTqVnpcRQItJJxqcuZmQ4DKR8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730537AbeLZW6E (ORCPT ); Wed, 26 Dec 2018 17:58:04 -0500 Received: from mail.kernel.org ([198.145.29.99]:58612 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730488AbeLZW5e (ORCPT ); Wed, 26 Dec 2018 17:57:34 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B163F218A5; Wed, 26 Dec 2018 22:57:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1545865054; bh=7rdMI+vpU5BXSaOm7tktjFG9kot4nRrYIaXL9lL/GPo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zeKQvkUx3ALt2MDgfUVcIGQZqCaootd/x9+Fe8L9itdrgYld1Lu7jqHA/wrH+trpS 9eWkKUrYy99w7kp3mOZzh7K7DHblfcC5LobXjY6Svuf0NsEQEMtwou9f2gQ/KeNajt pePTndoVF1ARPoJi2nTKp+udA60bc25h6YoK8/PM= From: Sasha Levin To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Juergen Gross , "David S . Miller" , Sasha Levin , netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.4 18/21] xen/netfront: tolerate frags with no data Date: Wed, 26 Dec 2018 17:54:56 -0500 Message-Id: <20181226225501.151365-18-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181226225501.151365-1-sashal@kernel.org> References: <20181226225501.151365-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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: Sasha Levin --- drivers/net/xen-netfront.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index 0a4bd73caae5..6f55ab4f7959 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -889,7 +889,7 @@ static RING_IDX xennet_fill_frags(struct netfront_queue *queue, 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)) { -- 2.19.1