From mboxrd@z Thu Jan 1 00:00:00 1970 From: t.figa@samsung.com (Tomasz Figa) Date: Thu, 15 May 2014 18:51:10 +0200 Subject: [PATCH] clk: divider: Fix overflow in clk_divider_bestdiv In-Reply-To: <1399479850-25292-1-git-send-email-t.figa@samsung.com> References: <1399479850-25292-1-git-send-email-t.figa@samsung.com> Message-ID: <5374F07E.9070106@samsung.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Mike, On 07.05.2014 18:24, Tomasz Figa wrote: > Commit c686078 ("clk: divider: Add round to closest divider") introduced > a helper function to check whether given divisor is the best one instead > of direct check. However due to int type used instead of unsigned long > for passing calculated rates to this function in certain cases an > overflow could occur, for example when trying to obtain maximum possible > clock rate by calling clk_round_rate(..., UINT_MAX). > > This patch fixes this issue by changing the type of rate, now and best > arguments of the function to unsigned long, which is the type that > should be used for clock rates. > > Signed-off-by: Tomasz Figa > --- > drivers/clk/clk-divider.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c > index c572945..e0b360a 100644 > --- a/drivers/clk/clk-divider.c > +++ b/drivers/clk/clk-divider.c > @@ -232,7 +232,7 @@ static int _div_round(struct clk_divider *divider, unsigned long parent_rate, > } > > static bool _is_best_div(struct clk_divider *divider, > - int rate, int now, int best) > + unsigned long rate, unsigned long now, unsigned long best) > { > if (divider->flags & CLK_DIVIDER_ROUND_CLOSEST) > return abs(rate - now) < abs(rate - best); > Ping. It's quite important fix as the issue makes all Exynos boards using sdhci-s3c almost unusable. Best regards, Tomasz From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754031AbaEOQvZ (ORCPT ); Thu, 15 May 2014 12:51:25 -0400 Received: from mailout2.w1.samsung.com ([210.118.77.12]:54601 "EHLO mailout2.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753897AbaEOQvX (ORCPT ); Thu, 15 May 2014 12:51:23 -0400 X-AuditID: cbfec7f4-b7fb36d000006ff7-21-5374f0833679 Message-id: <5374F07E.9070106@samsung.com> Date: Thu, 15 May 2014 18:51:10 +0200 From: Tomasz Figa Organization: Samsung R&D Institute Poland User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-version: 1.0 To: linux-arm-kernel@lists.infradead.org Cc: Mike Turquette , linux-kernel@vger.kernel.org, Maxime COQUELIN Subject: Re: [PATCH] clk: divider: Fix overflow in clk_divider_bestdiv References: <1399479850-25292-1-git-send-email-t.figa@samsung.com> In-reply-to: <1399479850-25292-1-git-send-email-t.figa@samsung.com> Content-type: text/plain; charset=ISO-8859-1 Content-transfer-encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFtrILMWRmVeSWpSXmKPExsVy+t/xq7rNH0qCDZ5MEbDY9Pgaq8XlXXPY LB6dXsxm8XTCRTYHFo871/aweWxeUu/x9MdeZo/Pm+QCWKK4bFJSczLLUov07RK4Mi69ky24 y13RsG0mWwPjXs4uRk4OCQETiZvdK5ggbDGJC/fWs4HYQgJLGSW65jN2MXIB2Z8ZJb7+PgVU xMHBK6AlseydNkgNi4CqxLJ598B62QTUJD43PALr5QcqWdN0nQWkXFQgQuLxBSGQMK+AoMSP yfdYQGwRAQ2JKV2P2UFsZoESiUs/7zCC2MICbhLLN95ngjjBSeLl9h6wkZwCzhKftl9lg6jX kdjfOg3KlpfYvOYt8wRGwVlIVsxCUjYLSdkCRuZVjKKppckFxUnpuYZ6xYm5xaV56XrJ+bmb GCHB/GUH4+JjVocYBTgYlXh4O/YXBwuxJpYVV+YeYpTgYFYS4TV/XhIsxJuSWFmVWpQfX1Sa k1p8iJGJg1OqgTGv91Th7jijd86exyXntpzbHvTGLC148beXFddSl8Q6nUzcFSgz68XUgKwX VWtXdt4QTFhpcO7eEyevKZ6f5rm+edbwPXRHkZlzZf+HtnitpGXB304Fsz1RYv0vdiXM4Xb/ h5I64d43wfJfXgoK59pIrJIV8ixZukh01Y4zL/lOp0r1tAsqhyuxFGckGmoxFxUnAgA5zYPn RAIAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Mike, On 07.05.2014 18:24, Tomasz Figa wrote: > Commit c686078 ("clk: divider: Add round to closest divider") introduced > a helper function to check whether given divisor is the best one instead > of direct check. However due to int type used instead of unsigned long > for passing calculated rates to this function in certain cases an > overflow could occur, for example when trying to obtain maximum possible > clock rate by calling clk_round_rate(..., UINT_MAX). > > This patch fixes this issue by changing the type of rate, now and best > arguments of the function to unsigned long, which is the type that > should be used for clock rates. > > Signed-off-by: Tomasz Figa > --- > drivers/clk/clk-divider.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c > index c572945..e0b360a 100644 > --- a/drivers/clk/clk-divider.c > +++ b/drivers/clk/clk-divider.c > @@ -232,7 +232,7 @@ static int _div_round(struct clk_divider *divider, unsigned long parent_rate, > } > > static bool _is_best_div(struct clk_divider *divider, > - int rate, int now, int best) > + unsigned long rate, unsigned long now, unsigned long best) > { > if (divider->flags & CLK_DIVIDER_ROUND_CLOSEST) > return abs(rate - now) < abs(rate - best); > Ping. It's quite important fix as the issue makes all Exynos boards using sdhci-s3c almost unusable. Best regards, Tomasz