From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752651AbdK3OJ0 (ORCPT ); Thu, 30 Nov 2017 09:09:26 -0500 Received: from mail-he1eur01on0122.outbound.protection.outlook.com ([104.47.0.122]:49600 "EHLO EUR01-HE1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751819AbdK3OJZ (ORCPT ); Thu, 30 Nov 2017 09:09:25 -0500 Date: Thu, 30 Nov 2017 15:09:15 +0100 From: Krzysztof Adamski To: Mark Brown , Greg Kroah-Hartman , linux-kernel@vger.kernel.org Subject: [PATCH] regmap: use proper part of work_buf for storing val Message-ID: <20171130140913.GA16598@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline User-Agent: Mutt/1.9.1 (2017-09-22) X-Originating-IP: [193.239.58.166] X-ClientProxiedBy: VI1PR0501CA0018.eurprd05.prod.outlook.com (2603:10a6:800:92::28) To VI1PR0702MB3790.eurprd07.prod.outlook.com (2603:10a6:803:4::11) X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-HT: Tenant X-MS-Office365-Filtering-Correlation-Id: 7cf3e6d4-6d45-4242-18d1-08d537fbf4ce X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:(48565401081)(5600026)(4604075)(4534020)(4602075)(4627115)(201703031133081)(201702281549075)(2017052603286);SRVR:VI1PR0702MB3790; 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While reg and val parts are always properly setup before each transaction, the pad part is left at its default value (zeros). Until it is overwritten, that is. _regmap_bus_read(), when calling _regmap_raw_read() uses beginning of work_buf as a place to store data read. Usually that is fine but if val_bits > reg_bits && pad_bits > 0, padding area of work_buf() may get overwritten. Since padding is not zeroed before each transaction, garbage will be used on next calls. This patch moves the val pointer used for _regmap_raw_read() to point to a part of work_buf intended for storing value read. Signed-off-by: Krzysztof Adamski --- drivers/base/regmap/regmap.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c index b9a779a4a739..d8806eac2708 100644 --- a/drivers/base/regmap/regmap.c +++ b/drivers/base/regmap/regmap.c @@ -2344,13 +2344,15 @@ static int _regmap_bus_read(void *context, unsigned int reg, { int ret; struct regmap *map = context; + void *work_val = map->work_buf + map->format.reg_bytes + + map->format.pad_bytes; if (!map->format.parse_val) return -EINVAL; - ret = _regmap_raw_read(map, reg, map->work_buf, map->format.val_bytes); + ret = _regmap_raw_read(map, reg, work_val, map->format.val_bytes); if (ret == 0) - *val = map->format.parse_val(map->work_buf); + *val = map->format.parse_val(work_val); return ret; } -- 2.13.6