1 files changed, 23 insertions, 24 deletions

diff --git a/kernel/watchdog_perf.c b/kernel/watchdog_perf.c
index 59c1d86a73a2..d3ca70e3c256 100644
--- a/kernel/watchdog_perf.c
+++ b/kernel/watchdog_perf.c
@@ -12,6 +12,7 @@
 
 #define pr_fmt(fmt) "NMI watchdog: " fmt
 
+#include <linux/panic.h>
 #include <linux/nmi.h>
 #include <linux/atomic.h>
 #include <linux/module.h>
@@ -21,8 +22,6 @@
 #include <linux/perf_event.h>
 
 static DEFINE_PER_CPU(struct perf_event *, watchdog_ev);
-static DEFINE_PER_CPU(struct perf_event *, dead_event);
-static struct cpumask dead_events_mask;
 
 static atomic_t watchdog_cpus = ATOMIC_INIT(0);
 
@@ -110,6 +109,9 @@ static void watchdog_overflow_callback(struct perf_event *event,
 	/* Ensure the watchdog never gets throttled */
 	event->hw.interrupts = 0;
 
+	if (panic_in_progress())
+		return;
+
 	if (!watchdog_check_timestamp())
 		return;
 
@@ -146,6 +148,7 @@ static int hardlockup_detector_event_create(void)
 			 PTR_ERR(evt));
 		return PTR_ERR(evt);
 	}
+	WARN_ONCE(this_cpu_read(watchdog_ev), "unexpected watchdog_ev leak");
 	this_cpu_write(watchdog_ev, evt);
 	return 0;
 }
@@ -181,34 +184,32 @@ void watchdog_hardlockup_disable(unsigned int cpu)
 
 	if (event) {
 		perf_event_disable(event);
+		perf_event_release_kernel(event);
 		this_cpu_write(watchdog_ev, NULL);
-		this_cpu_write(dead_event, event);
-		cpumask_set_cpu(smp_processor_id(), &dead_events_mask);
 		atomic_dec(&watchdog_cpus);
 	}
 }
 
 /**
- * hardlockup_detector_perf_cleanup - Cleanup disabled events and destroy them
- *
- * Called from lockup_detector_cleanup(). Serialized by the caller.
+ * hardlockup_detector_perf_adjust_period - Adjust the event period due
+ *                                          to current cpu frequency change
+ * @period: The target period to be set
  */
-void hardlockup_detector_perf_cleanup(void)
+void hardlockup_detector_perf_adjust_period(u64 period)
 {
-	int cpu;
+	struct perf_event *event = this_cpu_read(watchdog_ev);
 
-	for_each_cpu(cpu, &dead_events_mask) {
-		struct perf_event *event = per_cpu(dead_event, cpu);
+	if (!(watchdog_enabled & WATCHDOG_HARDLOCKUP_ENABLED))
+		return;
 
-		/*
-		 * Required because for_each_cpu() reports  unconditionally
-		 * CPU0 as set on UP kernels. Sigh.
-		 */
-		if (event)
-			perf_event_release_kernel(event);
-		per_cpu(dead_event, cpu) = NULL;
-	}
-	cpumask_clear(&dead_events_mask);
+	if (!event)
+		return;
+
+	if (event->attr.sample_period == period)
+		return;
+
+	if (perf_event_period(event, period))
+		pr_err("failed to change period to %llu\n", period);
 }
 
 /**
@@ -294,12 +295,10 @@ void __init hardlockup_config_perf_event(const char *str)
 	} else {
 		unsigned int len = comma - str;
 
-		if (len >= sizeof(buf))
+		if (len > sizeof(buf))
 			return;
 
-		if (strscpy(buf, str, sizeof(buf)) < 0)
-			return;
-		buf[len] = 0;
+		strscpy(buf, str, len);
 		if (kstrtoull(buf, 16, &config))
 			return;
 	}