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softlockup: fix softlockup_thresh unaligned access and disable detection at runtime

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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 <sivanich@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Dimitri Sivanich 2008-05-12 21:21:14 +02:00 committed by Thomas Gleixner
parent 9c44bc03ff
commit 9383d96790
3 changed files with 16 additions and 7 deletions
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2
include/linux/sched.h
View File

@ -295,10 +295,10 @@ extern void spawn_softlockup_task(void);
extern void touch_softlockup_watchdog(void); extern void touch_softlockup_watchdog(void);
extern void touch_all_softlockup_watchdogs(void); extern void touch_all_softlockup_watchdogs(void);
extern unsigned int softlockup_panic; extern unsigned int softlockup_panic;
extern unsigned long softlockup_thresh;
extern unsigned long sysctl_hung_task_check_count; extern unsigned long sysctl_hung_task_check_count;
extern unsigned long sysctl_hung_task_timeout_secs; extern unsigned long sysctl_hung_task_timeout_secs;
extern unsigned long sysctl_hung_task_warnings; extern unsigned long sysctl_hung_task_warnings;
extern int softlockup_thresh;
#else #else
static inline void softlockup_tick(void) static inline void softlockup_tick(void)
{ {

12
kernel/softlockup.c
View File

@ -25,7 +25,7 @@ static DEFINE_PER_CPU(unsigned long, print_timestamp);
static DEFINE_PER_CPU(struct task_struct *, watchdog_task); static DEFINE_PER_CPU(struct task_struct *, watchdog_task);
static int __read_mostly did_panic; 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 * 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(); struct pt_regs *regs = get_irq_regs();
unsigned long now; 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) { if (touch_timestamp == 0) {
touch_softlockup_watchdog(); touch_softlockup_watchdog();
return; return;
@ -104,7 +112,7 @@ void softlockup_tick(void)
/* report at most once a second */ /* report at most once a second */
if ((print_timestamp >= touch_timestamp && if ((print_timestamp >= touch_timestamp &&
print_timestamp < (touch_timestamp + 1)) || print_timestamp < (touch_timestamp + 1)) ||
did_panic || !per_cpu(watchdog_task, this_cpu)) { did_panic) {
return; return;
} }

9
kernel/sysctl.c
View File

@ -84,12 +84,13 @@ extern int latencytop_enabled;
extern int sysctl_nr_open_min, sysctl_nr_open_max; extern int sysctl_nr_open_min, sysctl_nr_open_max;
/* Constants used for minimum and maximum */ /* Constants used for minimum and maximum */
#if defined(CONFIG_DETECT_SOFTLOCKUP) || defined(CONFIG_HIGHMEM) #ifdef CONFIG_HIGHMEM
static int one = 1; static int one = 1;
#endif #endif
#ifdef CONFIG_DETECT_SOFTLOCKUP #ifdef CONFIG_DETECT_SOFTLOCKUP
static int sixty = 60; static int sixty = 60;
static int neg_one = -1;
#endif #endif
#ifdef CONFIG_MMU #ifdef CONFIG_MMU
@ -742,11 +743,11 @@ static struct ctl_table kern_table[] = {
.ctl_name = CTL_UNNUMBERED, .ctl_name = CTL_UNNUMBERED,
.procname = "softlockup_thresh", .procname = "softlockup_thresh",
.data = &softlockup_thresh, .data = &softlockup_thresh,
.maxlen = sizeof(unsigned long), .maxlen = sizeof(int),
.mode = 0644, .mode = 0644,
.proc_handler = &proc_doulongvec_minmax, .proc_handler = &proc_dointvec_minmax,
.strategy = &sysctl_intvec, .strategy = &sysctl_intvec,
.extra1 = &one, .extra1 = &neg_one,
.extra2 = &sixty, .extra2 = &sixty,
}, },
{ {