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: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/kernel/softlockup.c b/kernel/softlockup.c
index 78e0ad2..a3a0b23 100644
--- a/kernel/softlockup.c
+++ b/kernel/softlockup.c
@@ -25,7 +25,7 @@
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 @@
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 @@
/* 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 2d3b388..31c19a7 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -84,12 +84,13 @@
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 @@
.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,
},
{