Commit 9383d967 authored by Dimitri Sivanich's avatar Dimitri Sivanich Committed by Thomas Gleixner
Browse files

softlockup: fix softlockup_thresh unaligned access and disable detection at runtime 



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: default avatarDimitri Sivanich <sivanich@sgi.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 9c44bc03

include/linux/sched.h

+1 −1
Original line number Diff line number Diff line
@@ -295,10 +295,10 @@ extern void spawn_softlockup_task(void); 
extern void touch_softlockup_watchdog(void);

extern void touch_all_softlockup_watchdogs(void);

extern unsigned int  softlockup_panic;

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)

{

kernel/softlockup.c

+10 −2
Original line number Diff line number Diff line
@@ -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;



/*

 * Should we panic (and reboot, if panic_timeout= is set) when a
@@ -94,6 +94,14 @@ 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;
@@ -104,7 +112,7 @@ 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;

	}

kernel/sysctl.c

+5 −4
Original line number Diff line number Diff line
@@ -84,12 +84,13 @@ extern int latencytop_enabled; 
extern int sysctl_nr_open_min, sysctl_nr_open_max;



/* 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
@@ -742,11 +743,11 @@ 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,

	},

	{

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