diff --git a/collector/ethtool_linux.go b/collector/ethtool_linux.go
index 95bca73d..b7b413fc 100644
--- a/collector/ethtool_linux.go
+++ b/collector/ethtool_linux.go
@@ -422,7 +422,7 @@ func (c *ethtoolCollector) Update(ch chan<- prometheus.Metric) error {
 			val := stats[metric]
 
 			// Check to see if this metric exists; if not then create it and store it in c.entries.
-			entry := c.entry(metric, metricFQName)
+			entry := c.entryWithCreate(metric, metricFQName)
 			ch <- prometheus.MustNewConstMetric(
 				entry, prometheus.UntypedValue, float64(val), device)
 		}
@@ -431,7 +431,7 @@ func (c *ethtoolCollector) Update(ch chan<- prometheus.Metric) error {
 	return nil
 }
 
-func (c *ethtoolCollector) entry(key, metricFQName string) *prometheus.Desc {
+func (c *ethtoolCollector) entryWithCreate(key, metricFQName string) *prometheus.Desc {
 	c.entriesMutex.Lock()
 	defer c.entriesMutex.Unlock()
 
@@ -445,3 +445,9 @@ func (c *ethtoolCollector) entry(key, metricFQName string) *prometheus.Desc {
 
 	return c.entries[key]
 }
+
+func (c *ethtoolCollector) entry(key) *prometheus.Desc {
+	c.entriesMutex.Lock()
+	defer c.entriesMutex.Unlock()
+	return c.entries[key]
+}