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 0818CC43387 for ; Wed, 26 Dec 2018 22:48:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C16CA21741 for ; Wed, 26 Dec 2018 22:48:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1545864503; bh=zqKtLihkc+vmOLtpHm6K3OlFwhWxhtlzqtpKwOXBj+4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=sOGo0ukJiljIzVXvBQZs2j0nxoWlIzD7aVoQjRlkAxkyTR4ePfygnkweXgwCdJwHS IYE1yMxIhO6wcI0v7aHQvuClBZW1MyK9gjKbZZZwkI2gEeYb0F6goL1kZTrDNHk73N 1jYflM8V/iZ0dEhg9lwl3zNg5TjXxc5rimpmydOA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729869AbeLZWsW (ORCPT ); Wed, 26 Dec 2018 17:48:22 -0500 Received: from mail.kernel.org ([198.145.29.99]:38428 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728679AbeLZWiJ (ORCPT ); Wed, 26 Dec 2018 17:38:09 -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 8B5A6218EA; Wed, 26 Dec 2018 22:38:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1545863889; bh=zqKtLihkc+vmOLtpHm6K3OlFwhWxhtlzqtpKwOXBj+4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VdPW9YEL5iV7KkdTj2bKX4axYrJV4kf5iVqiqI9oeLxqwXkDDWoz58+VLFjhGTppv iUXV6g3nvOV98gxp82yDiwj2+mRgDWKsYYxVwF9QLEzplHrlYklPZdqoIRh1wRvDLP /RJamZcqqWMGP6nDUJrYsrx3BsccQgKMD/8F//LE= 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 4.19 78/97] xen/netfront: tolerate frags with no data Date: Wed, 26 Dec 2018 17:35:38 -0500 Message-Id: <20181226223557.149329-78-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181226223557.149329-1-sashal@kernel.org> References: <20181226223557.149329-1-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 f17f602e6171..5b97cc946d70 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -905,7 +905,7 @@ 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