From patchwork Sat Jan 11 09:50:50 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 1221605 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=default header.b=V4QwhqXo; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 47vwmh64JCz9sP6 for ; Sat, 11 Jan 2020 21:18:44 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730383AbgAKKSl (ORCPT ); Sat, 11 Jan 2020 05:18:41 -0500 Received: from mail.kernel.org ([198.145.29.99]:37136 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729838AbgAKKSl (ORCPT ); Sat, 11 Jan 2020 05:18:41 -0500 Received: from localhost (unknown [62.119.166.9]) (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 29A9020842; Sat, 11 Jan 2020 10:18:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578737920; bh=mcjFmwhwJrbakRmABQ1xRFN6l3QsdshO9EqfWV3t6OE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=V4QwhqXoiXRUBBEly3h4M+CMX/Qm9RO+rJdWfo3BiqYs+ceBM1ez9axlAixx60MXK +Kjus9Ke6fuJXbek4MlfDnMePv4SBlCNjKenf5gbIAQejuJfFd5tb7Bu/VAaf07g7c 9CxiLhsIbiEEo3MV2ELW1sWp2IAroeuvwZkbYCkc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Wen Yang , Kevin Darbyshire-Bryant , =?utf-8?q?Toke_H=C3=B8iland-J=C3=B8rg?= =?utf-8?q?ensen?= , "David S. Miller" , Cong Wang , cake@lists.bufferbloat.net, netdev@vger.kernel.org, =?utf-8?q?Toke_H=C3=B8iland-J=C3=B8rgensen?= Subject: [PATCH 4.19 73/84] sch_cake: avoid possible divide by zero in cake_enqueue() Date: Sat, 11 Jan 2020 10:50:50 +0100 Message-Id: <20200111094911.801043901@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200111094845.328046411@linuxfoundation.org> References: <20200111094845.328046411@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Wen Yang [ Upstream commit 68aab823c223646fab311f8a6581994facee66a0 ] The variables 'window_interval' is u64 and do_div() truncates it to 32 bits, which means it can test non-zero and be truncated to zero for division. The unit of window_interval is nanoseconds, so its lower 32-bit is relatively easy to exceed. Fix this issue by using div64_u64() instead. Fixes: 7298de9cd725 ("sch_cake: Add ingress mode") Signed-off-by: Wen Yang Cc: Kevin Darbyshire-Bryant Cc: Toke Høiland-Jørgensen Cc: David S. Miller Cc: Cong Wang Cc: cake@lists.bufferbloat.net Cc: netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org Acked-by: Toke Høiland-Jørgensen Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/sched/sch_cake.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/sched/sch_cake.c +++ b/net/sched/sch_cake.c @@ -1758,7 +1758,7 @@ static s32 cake_enqueue(struct sk_buff * q->avg_window_begin)); u64 b = q->avg_window_bytes * (u64)NSEC_PER_SEC; - do_div(b, window_interval); + b = div64_u64(b, window_interval); q->avg_peak_bandwidth = cake_ewma(q->avg_peak_bandwidth, b, b > q->avg_peak_bandwidth ? 2 : 8);