From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753425Ab3IWIoU (ORCPT ); Mon, 23 Sep 2013 04:44:20 -0400 Received: from szxga01-in.huawei.com ([119.145.14.64]:60077 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752882Ab3IWIoT (ORCPT ); Mon, 23 Sep 2013 04:44:19 -0400 Message-ID: <523FFF4E.9050401@huawei.com> Date: Mon, 23 Sep 2013 16:43:58 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:17.0) Gecko/20130801 Thunderbird/17.0.8 MIME-Version: 1.0 To: Andrew Morton CC: Ingo Molnar , LKML Subject: [PATCH v2] hung_task: change sysctl_hung_task_check_count to int Content-Type: text/plain; charset="GB2312" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.135.68.215] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org As sysctl_hung_task_check_count is unsigned long, when this value is assigned to max_count in check_hung_uninterruptible_tasks(), it's truncated to int type. Therefore if we write 2^32 to sysctl.hung_task_check_count, hung task detection will be effectively disabled. With this fix, it will still truncate the user input, but reading sysctl.hung_task_check_count reflects the truncated value. v2: limit lowest value to 0. Signed-off-by: Li Zefan Acked-by: Ingo Molnar --- include/linux/sched/sysctl.h | 2 +- kernel/hung_task.c | 2 +- kernel/sysctl.c | 5 +++-- 3 files changed, 5 insertions(+), 4 deletions(-) diff --git a/include/linux/sched/sysctl.h b/include/linux/sched/sysctl.h index bf8086b..9552afa 100644 --- a/include/linux/sched/sysctl.h +++ b/include/linux/sched/sysctl.h @@ -2,8 +2,8 @@ #define _SCHED_SYSCTL_H #ifdef CONFIG_DETECT_HUNG_TASK +extern int sysctl_hung_task_check_count; extern unsigned int sysctl_hung_task_panic; -extern unsigned long sysctl_hung_task_check_count; extern unsigned long sysctl_hung_task_timeout_secs; extern unsigned long sysctl_hung_task_warnings; extern int proc_dohung_task_timeout_secs(struct ctl_table *table, int write, diff --git a/kernel/hung_task.c b/kernel/hung_task.c index 3e97fb1..0422523 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -20,7 +20,7 @@ /* * The number of tasks checked: */ -unsigned long __read_mostly sysctl_hung_task_check_count = PID_MAX_LIMIT; +int __read_mostly sysctl_hung_task_check_count = PID_MAX_LIMIT; /* * Limit number of tasks checked in a batch. diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 7453418..bcb35ab 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -962,9 +962,10 @@ static struct ctl_table kern_table[] = { { .procname = "hung_task_check_count", .data = &sysctl_hung_task_check_count, - .maxlen = sizeof(unsigned long), + .maxlen = sizeof(int), .mode = 0644, - .proc_handler = proc_doulongvec_minmax, + .proc_handler = proc_dointvec_minmax, + .extra1 = &zero, }, { .procname = "hung_task_timeout_secs", -- 1.8.0.2