4 files changed, 29 insertions, 11 deletions

diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index 2f52ec0..d6717a3 100644
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -244,7 +244,7 @@ static void sugov_iowait_boost(struct sugov_cpu *sg_cpu, unsigned long *util,
 #ifdef CONFIG_NO_HZ_COMMON
 static bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu)
 {
-	unsigned long idle_calls = tick_nohz_get_idle_calls();
+	unsigned long idle_calls = tick_nohz_get_idle_calls_cpu(sg_cpu->cpu);
 	bool ret = idle_calls == sg_cpu->saved_idle_calls;
 
 	sg_cpu->saved_idle_calls = idle_calls;
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 99578f0..77555fa 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -986,6 +986,19 @@ ktime_t tick_nohz_get_sleep_length(void)
 }
 
 /**
+ * tick_nohz_get_idle_calls_cpu - return the current idle calls counter value
+ * for a particular CPU.
+ *
+ * Called from the schedutil frequency scaling governor in scheduler context.
+ */
+unsigned long tick_nohz_get_idle_calls_cpu(int cpu)
+{
+	struct tick_sched *ts = tick_get_tick_sched(cpu);
+
+	return ts->idle_calls;
+}
+
+/**
  * tick_nohz_get_idle_calls - return the current idle calls counter value
  *
  * Called from the schedutil frequency scaling governor in scheduler context.
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index c87766c..9ab1899 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -280,6 +280,8 @@ EXPORT_SYMBOL_GPL(ring_buffer_event_data);
 /* Missed count stored at end */
 #define RB_MISSED_STORED	(1 << 30)
 
+#define RB_MISSED_FLAGS		(RB_MISSED_EVENTS|RB_MISSED_STORED)
+
 struct buffer_data_page {
 	u64		 time_stamp;	/* page time stamp */
 	local_t		 commit;	/* write committed index */
@@ -331,7 +333,9 @@ static void rb_init_page(struct buffer_data_page *bpage)
  */
 size_t ring_buffer_page_len(void *page)
 {
-	return local_read(&((struct buffer_data_page *)page)->commit)
+	struct buffer_data_page *bpage = page;
+
+	return (local_read(&bpage->commit) & ~RB_MISSED_FLAGS)
 		+ BUF_PAGE_HDR_SIZE;
 }
 
@@ -4400,8 +4404,13 @@ void ring_buffer_free_read_page(struct ring_buffer *buffer, int cpu, void *data)
 {
 	struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
 	struct buffer_data_page *bpage = data;
+	struct page *page = virt_to_page(bpage);
 	unsigned long flags;
 
+	/* If the page is still in use someplace else, we can't reuse it */
+	if (page_ref_count(page) > 1)
+		goto out;
+
 	local_irq_save(flags);
 	arch_spin_lock(&cpu_buffer->lock);
 
@@ -4413,6 +4422,7 @@ void ring_buffer_free_read_page(struct ring_buffer *buffer, int cpu, void *data)
 	arch_spin_unlock(&cpu_buffer->lock);
 	local_irq_restore(flags);
 
+ out:
 	free_page((unsigned long)bpage);
 }
 EXPORT_SYMBOL_GPL(ring_buffer_free_read_page);
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 59518b8..2a8d8a2 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -6769,7 +6769,7 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
 		.spd_release	= buffer_spd_release,
 	};
 	struct buffer_ref *ref;
-	int entries, size, i;
+	int entries, i;
 	ssize_t ret = 0;
 
 #ifdef CONFIG_TRACER_MAX_TRACE
@@ -6823,14 +6823,6 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
 			break;
 		}
 
-		/*
-		 * zero out any left over data, this is going to
-		 * user land.
-		 */
-		size = ring_buffer_page_len(ref->page);
-		if (size < PAGE_SIZE)
-			memset(ref->page + size, 0, PAGE_SIZE - size);
-
 		page = virt_to_page(ref->page);
 
 		spd.pages[i] = page;
@@ -7588,6 +7580,7 @@ allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size
 	buf->data = alloc_percpu(struct trace_array_cpu);
 	if (!buf->data) {
 		ring_buffer_free(buf->buffer);
+		buf->buffer = NULL;
 		return -ENOMEM;
 	}
 
@@ -7611,7 +7604,9 @@ static int allocate_trace_buffers(struct trace_array *tr, int size)
 				    allocate_snapshot ? size : 1);
 	if (WARN_ON(ret)) {
 		ring_buffer_free(tr->trace_buffer.buffer);
+		tr->trace_buffer.buffer = NULL;
 		free_percpu(tr->trace_buffer.data);
+		tr->trace_buffer.data = NULL;
 		return -ENOMEM;
 	}
 	tr->allocated_snapshot = allocate_snapshot;