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=-14.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 CA1F7C76186 for ; Mon, 29 Jul 2019 20:06:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8E042205F4 for ; Mon, 29 Jul 2019 20:06:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564430796; bh=5QHtL0XNAjyJtuF2bZOQbdAb4gdb/YztsPUiD+UjgXg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=AcuCNmqcF75bVX6XEzz8lQpN2gHjYJDay83BEsA6/3PLfL9sGCX7Qk6FnmVE/pnaw TaofmrdQOV1xIJKUMEBbiYqgogX1gwCn57LuJ/nJoB7ENlWO8gQh9PXXThcS4bN1fp aw1X3G7FzWiSJZgezLBpBMUHfbT6lLGct2L6mTrQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389285AbfG2TlO (ORCPT ); Mon, 29 Jul 2019 15:41:14 -0400 Received: from mail.kernel.org ([198.145.29.99]:56520 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389256AbfG2TlG (ORCPT ); Mon, 29 Jul 2019 15:41:06 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 A080220C01; Mon, 29 Jul 2019 19:41:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564429265; bh=5QHtL0XNAjyJtuF2bZOQbdAb4gdb/YztsPUiD+UjgXg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QhIlWxU63lZ4pS6EaT6oyrlG24wcyvp4kRHMZ1hxv0eRvr3LfQfwdexkG/FJE3L/+ CAjiVCxzQwUsM/zyYbCpV/kOomVyGOmyCssnQvrlyWlDUc0rJB2xic751zICsQxMyY sG+kRgMeU0ZLosTeLTMJL9Ufas9crH5rjyz9ZK2Q= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Bastien Nocera , Jonathan Cameron , Sasha Levin Subject: [PATCH 4.19 044/113] iio: iio-utils: Fix possible incorrect mask calculation Date: Mon, 29 Jul 2019 21:22:11 +0200 Message-Id: <20190729190706.217460325@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190729190655.455345569@linuxfoundation.org> References: <20190729190655.455345569@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ Upstream commit 208a68c8393d6041a90862992222f3d7943d44d6 ] On some machines, iio-sensor-proxy was returning all 0's for IIO sensor values. It turns out that the bits_used for this sensor is 32, which makes the mask calculation: *mask = (1 << 32) - 1; If the compiler interprets the 1 literals as 32-bit ints, it generates undefined behavior depending on compiler version and optimization level. On my system, it optimizes out the shift, so the mask value becomes *mask = (1) - 1; With a mask value of 0, iio-sensor-proxy will always return 0 for every axis. Avoid incorrect 0 values caused by compiler optimization. See original fix by Brett Dutro in iio-sensor-proxy: https://github.com/hadess/iio-sensor-proxy/commit/9615ceac7c134d838660e209726cd86aa2064fd3 Signed-off-by: Bastien Nocera Signed-off-by: Jonathan Cameron Signed-off-by: Sasha Levin --- tools/iio/iio_utils.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/iio/iio_utils.c b/tools/iio/iio_utils.c index 7a6d61c6c012..55272fef3b50 100644 --- a/tools/iio/iio_utils.c +++ b/tools/iio/iio_utils.c @@ -159,9 +159,9 @@ int iioutils_get_type(unsigned *is_signed, unsigned *bytes, unsigned *bits_used, *be = (endianchar == 'b'); *bytes = padint / 8; if (*bits_used == 64) - *mask = ~0; + *mask = ~(0ULL); else - *mask = (1ULL << *bits_used) - 1; + *mask = (1ULL << *bits_used) - 1ULL; *is_signed = (signchar == 's'); if (fclose(sysfsfp)) { -- 2.20.1