From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 457913B2A4 for ; Sat, 11 Jan 2020 05:18:41 -0500 (EST) 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=20H=C3=B8iland-J=C3=B8rgensen?= , "David S. Miller" , Cong Wang , cake@lists.bufferbloat.net, netdev@vger.kernel.org, =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= 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 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Mailman-Approved-At: Sat, 11 Jan 2020 10:59:44 -0500 Subject: [Cake] [PATCH 4.19 73/84] sch_cake: avoid possible divide by zero in cake_enqueue() X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Cake - FQ_codel the next generation List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 11 Jan 2020 10:18:41 -0000 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);