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 08D57ECDE46 for ; Thu, 25 Oct 2018 14:17:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B4FC22085A for ; Thu, 25 Oct 2018 14:17:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="buw5FwGt" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B4FC22085A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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 S1729646AbeJYWuZ (ORCPT ); Thu, 25 Oct 2018 18:50:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:59784 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729604AbeJYWuY (ORCPT ); Thu, 25 Oct 2018 18:50:24 -0400 Received: from sasha-vm.mshome.net (unknown [167.98.65.38]) (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 759B420834; Thu, 25 Oct 2018 14:17:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1540477047; bh=8/q8lDxAVbsbhJxG2nfrAxcBPW8AmLMl7jfGy5upL9Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=buw5FwGtrbjnXF9O4QW9Wr4br9rQdxGw2UvjRTukm1B5pHrxo3LSruPS0xtVkJFV4 v8NflFw7sUDyE1+fzxrLchKXjQGb+hOJE+C6UMSRlGMmqW6ko0IQG0BPYqOAeRq9PG SlVjZ/0I0d0FjP7onyXAX6/axrImLxWQI+pOULQQ= From: Sasha Levin To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Eugenia Emantayev , Tariq Toukan , "David S . Miller" , Sasha Levin Subject: [PATCH AUTOSEL 4.4 11/65] net/mlx4_en: Resolve dividing by zero in 32-bit system Date: Thu, 25 Oct 2018 10:16:11 -0400 Message-Id: <20181025141705.213937-11-sashal@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181025141705.213937-1-sashal@kernel.org> References: <20181025141705.213937-1-sashal@kernel.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Eugenia Emantayev [ Upstream commit 4850cf4581578216468b7b3c3d06cc5abb0a697d ] When doing roundup_pow_of_two for large enough number with bit 31, an overflow will occur and a value equal to 1 will be returned. In this case 1 will be subtracted from the return value and division by zero will be reached. Fixes: 31c128b66e5b ("net/mlx4_en: Choose time-stamping shift value according to HW frequency") Signed-off-by: Eugenia Emantayev Signed-off-by: Tariq Toukan Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/ethernet/mellanox/mlx4/en_clock.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/en_clock.c b/drivers/net/ethernet/mellanox/mlx4/en_clock.c index 4dccf7287f0f..52e4ed2f639d 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_clock.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_clock.c @@ -251,8 +251,11 @@ static u32 freq_to_shift(u16 freq) { u32 freq_khz = freq * 1000; u64 max_val_cycles = freq_khz * 1000 * MLX4_EN_WRAP_AROUND_SEC; + u64 tmp_rounded = + roundup_pow_of_two(max_val_cycles) > max_val_cycles ? + roundup_pow_of_two(max_val_cycles) - 1 : UINT_MAX; u64 max_val_cycles_rounded = is_power_of_2(max_val_cycles + 1) ? - max_val_cycles : roundup_pow_of_two(max_val_cycles) - 1; + max_val_cycles : tmp_rounded; /* calculate max possible multiplier in order to fit in 64bit */ u64 max_mul = div_u64(0xffffffffffffffffULL, max_val_cycles_rounded); -- 2.17.1