From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935073AbYEBM5A (ORCPT ); Fri, 2 May 2008 08:57:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1764363AbYEBM4u (ORCPT ); Fri, 2 May 2008 08:56:50 -0400 Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:50093 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1761650AbYEBM4q (ORCPT ); Fri, 2 May 2008 08:56:46 -0400 Date: Fri, 2 May 2008 07:56:44 -0500 From: Dimitri Sivanich To: Ingo Molnar , linux-kernel@vger.kernel.org Cc: Thomas Gleixner , Peter Zijlstra Subject: [PATCH] Fix softlockup_thresh unaligned access and disable detection at runtime Message-ID: <20080502125644.GA31059@sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Fix unaligned access errors when setting softlockup_thresh on 64 bit platforms. Allow softlockup detection to be disabled by setting softlockup_thresh <= 0. Detect that boot time softlockup detection has been disabled earlier in softlockup_tick. Signed-off-by: Dimitri Sivanich --- include/linux/sched.h | 2 +- kernel/softlockup.c | 12 ++++++++++-- kernel/sysctl.c | 9 +++++---- 3 files changed, 16 insertions(+), 7 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 03c2380..d61e9b7 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -292,10 +292,10 @@ extern void softlockup_tick(void); extern void spawn_softlockup_task(void); extern void touch_softlockup_watchdog(void); extern void touch_all_softlockup_watchdogs(void); -extern unsigned long softlockup_thresh; 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 softlockup_thresh; #else static inline void softlockup_tick(void) { diff --git a/kernel/softlockup.c b/kernel/softlockup.c index 01b6522..ef60e7c 100644 --- a/kernel/softlockup.c +++ b/kernel/softlockup.c @@ -25,7 +25,7 @@ static DEFINE_PER_CPU(unsigned long, print_timestamp); static DEFINE_PER_CPU(struct task_struct *, watchdog_task); static int __read_mostly did_panic; -unsigned long __read_mostly softlockup_thresh = 60; +int __read_mostly softlockup_thresh = 60; static int softlock_panic(struct notifier_block *this, unsigned long event, void *ptr) @@ -79,6 +79,14 @@ void softlockup_tick(void) struct pt_regs *regs = get_irq_regs(); unsigned long now; + /* Is detection switched off? */ + if (!per_cpu(watchdog_task, this_cpu) || softlockup_thresh <= 0) { + /* Be sure we don't false trigger if switched back on */ + if (touch_timestamp) + per_cpu(touch_timestamp, this_cpu) = 0; + return; + } + if (touch_timestamp == 0) { touch_softlockup_watchdog(); return; @@ -89,7 +97,7 @@ void softlockup_tick(void) /* report at most once a second */ if ((print_timestamp >= touch_timestamp && print_timestamp < (touch_timestamp + 1)) || - did_panic || !per_cpu(watchdog_task, this_cpu)) { + did_panic) { return; } diff --git a/kernel/sysctl.c b/kernel/sysctl.c index d7ffdc5..d68c77a 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -83,12 +83,13 @@ extern int sysctl_stat_interval; extern int latencytop_enabled; /* Constants used for minimum and maximum */ -#if defined(CONFIG_DETECT_SOFTLOCKUP) || defined(CONFIG_HIGHMEM) +#ifdef CONFIG_HIGHMEM static int one = 1; #endif #ifdef CONFIG_DETECT_SOFTLOCKUP static int sixty = 60; +static int neg_one = -1; #endif #ifdef CONFIG_MMU @@ -730,11 +731,11 @@ static struct ctl_table kern_table[] = { .ctl_name = CTL_UNNUMBERED, .procname = "softlockup_thresh", .data = &softlockup_thresh, - .maxlen = sizeof(unsigned long), + .maxlen = sizeof(int), .mode = 0644, - .proc_handler = &proc_doulongvec_minmax, + .proc_handler = &proc_dointvec_minmax, .strategy = &sysctl_intvec, - .extra1 = &one, + .extra1 = &neg_one, .extra2 = &sixty, }, { -- 1.5.4.rc3