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-rw-r--r--include/linux/nmi.h1
-rw-r--r--kernel/watchdog.c37
-rw-r--r--kernel/watchdog_hld.c7
3 files changed, 19 insertions, 26 deletions
diff --git a/include/linux/nmi.h b/include/linux/nmi.h
index 80354e6fa86d..91a3a4a4c8ae 100644
--- a/include/linux/nmi.h
+++ b/include/linux/nmi.h
@@ -27,7 +27,6 @@ extern void touch_softlockup_watchdog_sync(void);
extern void touch_all_softlockup_watchdogs(void);
extern unsigned int softlockup_panic;
extern int soft_watchdog_enabled;
-extern atomic_t watchdog_park_in_progress;
#else
static inline void touch_softlockup_watchdog_sched(void)
{
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index dd1fd59683c5..c290135fb415 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -136,8 +136,6 @@ void __weak watchdog_nmi_reconfigure(void)
#define for_each_watchdog_cpu(cpu) \
for_each_cpu_and((cpu), cpu_online_mask, &watchdog_cpumask)
-atomic_t watchdog_park_in_progress = ATOMIC_INIT(0);
-
static u64 __read_mostly sample_period;
static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts);
@@ -322,8 +320,7 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
int duration;
int softlockup_all_cpu_backtrace = sysctl_softlockup_all_cpu_backtrace;
- if (!watchdog_enabled ||
- atomic_read(&watchdog_park_in_progress) != 0)
+ if (!watchdog_enabled)
return HRTIMER_NORESTART;
/* kick the hardlockup detector */
@@ -437,32 +434,37 @@ static void watchdog_set_prio(unsigned int policy, unsigned int prio)
static void watchdog_enable(unsigned int cpu)
{
- struct hrtimer *hrtimer = raw_cpu_ptr(&watchdog_hrtimer);
+ struct hrtimer *hrtimer = this_cpu_ptr(&watchdog_hrtimer);
- /* kick off the timer for the hardlockup detector */
+ /*
+ * Start the timer first to prevent the NMI watchdog triggering
+ * before the timer has a chance to fire.
+ */
hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
hrtimer->function = watchdog_timer_fn;
+ hrtimer_start(hrtimer, ns_to_ktime(sample_period),
+ HRTIMER_MODE_REL_PINNED);
+ /* Initialize timestamp */
+ __touch_watchdog();
/* Enable the perf event */
watchdog_nmi_enable(cpu);
- /* done here because hrtimer_start can only pin to smp_processor_id() */
- hrtimer_start(hrtimer, ns_to_ktime(sample_period),
- HRTIMER_MODE_REL_PINNED);
-
- /* initialize timestamp */
watchdog_set_prio(SCHED_FIFO, MAX_RT_PRIO - 1);
- __touch_watchdog();
}
static void watchdog_disable(unsigned int cpu)
{
- struct hrtimer *hrtimer = raw_cpu_ptr(&watchdog_hrtimer);
+ struct hrtimer *hrtimer = this_cpu_ptr(&watchdog_hrtimer);
watchdog_set_prio(SCHED_NORMAL, 0);
- hrtimer_cancel(hrtimer);
- /* disable the perf event */
+ /*
+ * Disable the perf event first. That prevents that a large delay
+ * between disabling the timer and disabling the perf event causes
+ * the perf NMI to detect a false positive.
+ */
watchdog_nmi_disable(cpu);
+ hrtimer_cancel(hrtimer);
}
static void watchdog_cleanup(unsigned int cpu, bool online)
@@ -518,16 +520,11 @@ static int watchdog_park_threads(void)
{
int cpu, ret = 0;
- atomic_set(&watchdog_park_in_progress, 1);
-
for_each_watchdog_cpu(cpu) {
ret = kthread_park(per_cpu(softlockup_watchdog, cpu));
if (ret)
break;
}
-
- atomic_set(&watchdog_park_in_progress, 0);
-
return ret;
}
diff --git a/kernel/watchdog_hld.c b/kernel/watchdog_hld.c
index 94111ccb09b5..0aa191ee3d51 100644
--- a/kernel/watchdog_hld.c
+++ b/kernel/watchdog_hld.c
@@ -106,15 +106,12 @@ static struct perf_event_attr wd_hw_attr = {
/* Callback function for perf event subsystem */
static void watchdog_overflow_callback(struct perf_event *event,
- struct perf_sample_data *data,
- struct pt_regs *regs)
+ struct perf_sample_data *data,
+ struct pt_regs *regs)
{
/* Ensure the watchdog never gets throttled */
event->hw.interrupts = 0;
- if (atomic_read(&watchdog_park_in_progress) != 0)
- return;
-
if (__this_cpu_read(watchdog_nmi_touch) == true) {
__this_cpu_write(watchdog_nmi_touch, false);
return;