diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 748f640..b2af14e 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1710,9 +1710,11 @@
 
 static void trace_iterator_increment(struct trace_iterator *iter)
 {
+	struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, iter->cpu);
+
 	iter->idx++;
-	if (iter->buffer_iter[iter->cpu])
-		ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
+	if (buf_iter)
+		ring_buffer_read(buf_iter, NULL);
 }
 
 static struct trace_entry *
@@ -1720,7 +1722,7 @@
 		unsigned long *lost_events)
 {
 	struct ring_buffer_event *event;
-	struct ring_buffer_iter *buf_iter = iter->buffer_iter[cpu];
+	struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, cpu);
 
 	if (buf_iter)
 		event = ring_buffer_iter_peek(buf_iter, ts);
@@ -1858,10 +1860,10 @@
 
 	tr->data[cpu]->skipped_entries = 0;
 
-	if (!iter->buffer_iter[cpu])
+	buf_iter = trace_buffer_iter(iter, cpu);
+	if (!buf_iter)
 		return;
 
-	buf_iter = iter->buffer_iter[cpu];
 	ring_buffer_iter_reset(buf_iter);
 
 	/*
@@ -2207,13 +2209,15 @@
 
 int trace_empty(struct trace_iterator *iter)
 {
+	struct ring_buffer_iter *buf_iter;
 	int cpu;
 
 	/* If we are looking at one CPU buffer, only check that one */
 	if (iter->cpu_file != TRACE_PIPE_ALL_CPU) {
 		cpu = iter->cpu_file;
-		if (iter->buffer_iter[cpu]) {
-			if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
+		buf_iter = trace_buffer_iter(iter, cpu);
+		if (buf_iter) {
+			if (!ring_buffer_iter_empty(buf_iter))
 				return 0;
 		} else {
 			if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
@@ -2223,8 +2227,9 @@
 	}
 
 	for_each_tracing_cpu(cpu) {
-		if (iter->buffer_iter[cpu]) {
-			if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
+		buf_iter = trace_buffer_iter(iter, cpu);
+		if (buf_iter) {
+			if (!ring_buffer_iter_empty(buf_iter))
 				return 0;
 		} else {
 			if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
@@ -2383,6 +2388,8 @@
 	if (!iter)
 		return ERR_PTR(-ENOMEM);
 
+	iter->buffer_iter = kzalloc(sizeof(*iter->buffer_iter) * num_possible_cpus(),
+				    GFP_KERNEL);
 	/*
 	 * We make a copy of the current tracer to avoid concurrent
 	 * changes on it while we are reading.
@@ -2443,6 +2450,7 @@
  fail:
 	mutex_unlock(&trace_types_lock);
 	kfree(iter->trace);
+	kfree(iter->buffer_iter);
 	seq_release_private(inode, file);
 	return ERR_PTR(-ENOMEM);
 }
@@ -2483,6 +2491,7 @@
 	mutex_destroy(&iter->mutex);
 	free_cpumask_var(iter->started);
 	kfree(iter->trace);
+	kfree(iter->buffer_iter);
 	seq_release_private(inode, file);
 	return 0;
 }