From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751872AbdBFSYq (ORCPT ); Mon, 6 Feb 2017 13:24:46 -0500 Received: from mail-yw0-f194.google.com ([209.85.161.194]:35112 "EHLO mail-yw0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750997AbdBFSYp (ORCPT ); Mon, 6 Feb 2017 13:24:45 -0500 Date: Mon, 6 Feb 2017 13:24:42 -0500 From: Tejun Heo To: Martin Steigerwald Cc: Peter Zijlstra , Ingo Molnar , Andrew Morton , Ingo Molnar , LKML , Nicolas Dichtel , Jay Lan , Martin Steigerwald , Gerlof Langeveld , Marc Haber , Ben Hutchings , Balbir Singh , kernel-team@fb.com Subject: [PATCH] cpumask: use nr_cpumask_bits for parsing functions Message-ID: <20170206182442.GB31078@htj.duckdns.org> References: <5967400.cFS0L5jxeH@merkaba> <20161219172549.GK3107@twins.programming.kicks-ass.net> <5854646.yRl4qIL1ZN@merkaba> <20170206162027.GA31078@htj.duckdns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170206162027.GA31078@htj.duckdns.org> User-Agent: Mutt/1.7.1 (2016-10-04) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 513e3d2d11c9 ("cpumask: always use nr_cpu_ids in formatting and parsing functions") converted both cpumask printing and parsing functions to use nr_cpu_ids instead of nr_cpumask_bits. While this was okay for the printing functions as it just picked one of the two output formats that we were alternating between depending on a kernel config, doing the same for parsing wasn't okay. nr_cpumask_bits can be either nr_cpu_ids or NR_CPUS. We can always use nr_cpu_ids but that is a variable while NR_CPUS is a constant, so it can be more efficient to use NR_CPUS when we can get away with it. Converting the printing functions to nr_cpu_ids makes sense because it affects how the masks get presented to userspace and doesn't break anything; however, using nr_cpu_ids for parsing functions can incorrectly leave the higher bits uninitialized while reading in these masks from userland. As all testing and comparison functions use nr_cpumask_bits which can be larger than nr_cpu_ids, the parsed cpumasks can erroneously yield false negative results. This made the taskstats interface incorrectly return -EINVAL even when the inputs were correct. Fix it by restoring the parse functions to use nr_cpumask_bits instead of nr_cpu_ids. Signed-off-by: Tejun Heo Fixes: 513e3d2d11c9 ("cpumask: always use nr_cpu_ids in formatting and parsing functions") Cc: stable@vger.kernel.org # v4.0+ Reported-by: Martin Steigerwald Debugged-by: Ben Hutchings --- include/linux/cpumask.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index c717f5e..b3d2c1a 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -560,7 +560,7 @@ static inline void cpumask_copy(struct cpumask *dstp, static inline int cpumask_parse_user(const char __user *buf, int len, struct cpumask *dstp) { - return bitmap_parse_user(buf, len, cpumask_bits(dstp), nr_cpu_ids); + return bitmap_parse_user(buf, len, cpumask_bits(dstp), nr_cpumask_bits); } /** @@ -575,7 +575,7 @@ static inline int cpumask_parselist_user(const char __user *buf, int len, struct cpumask *dstp) { return bitmap_parselist_user(buf, len, cpumask_bits(dstp), - nr_cpu_ids); + nr_cpumask_bits); } /** @@ -590,7 +590,7 @@ static inline int cpumask_parse(const char *buf, struct cpumask *dstp) char *nl = strchr(buf, '\n'); unsigned int len = nl ? (unsigned int)(nl - buf) : strlen(buf); - return bitmap_parse(buf, len, cpumask_bits(dstp), nr_cpu_ids); + return bitmap_parse(buf, len, cpumask_bits(dstp), nr_cpumask_bits); } /** @@ -602,7 +602,7 @@ static inline int cpumask_parse(const char *buf, struct cpumask *dstp) */ static inline int cpulist_parse(const char *buf, struct cpumask *dstp) { - return bitmap_parselist(buf, cpumask_bits(dstp), nr_cpu_ids); + return bitmap_parselist(buf, cpumask_bits(dstp), nr_cpumask_bits); } /**