diff --git a/dnsfilter/dnsfilter_test.go b/dnsfilter/dnsfilter_test.go
index bbb01ac0..b617dd41 100644
--- a/dnsfilter/dnsfilter_test.go
+++ b/dnsfilter/dnsfilter_test.go
@@ -654,13 +654,19 @@ func TestCheckHostSafeSearchGoogle(t *testing.T) {
 	}
 }
 
-func TestSafeSearchCacheYandex (t *testing.T) {
+func TestSafeSearchCacheYandex(t *testing.T) {
 	d := NewForTest()
 	defer d.Destroy()
 	domain := "yandex.ru"
 
+	var result Result
+	var err error
+
 	// Check host with disabled safesearch
-	result, err := d.CheckHost(domain)
+	result, err = d.CheckHost(domain)
+	if err != nil {
+		t.Fatalf("Cannot check host due to %s", err)
+	}
 	if result.IP != nil {
 		t.Fatalf("SafeSearch is not enabled but there is an answer for `%s` !", domain)
 	}
@@ -693,11 +699,14 @@ func TestSafeSearchCacheYandex (t *testing.T) {
 	}
 }
 
-func TestSafeSearchCacheGoogle (t *testing.T) {
+func TestSafeSearchCacheGoogle(t *testing.T) {
 	d := NewForTest()
 	defer d.Destroy()
 	domain := "www.google.ru"
 	result, err := d.CheckHost(domain)
+	if err != nil {
+		t.Fatalf("Cannot check host due to %s", err)
+	}
 	if result.IP != nil {
 		t.Fatalf("SafeSearch is not enabled but there is an answer!")
 	}
diff --git a/dnsfilter/safesearch.go b/dnsfilter/safesearch.go
index c4834b2f..d7f4ce07 100644
--- a/dnsfilter/safesearch.go
+++ b/dnsfilter/safesearch.go
@@ -1,11 +1,11 @@
 package dnsfilter
 
 var safeSearchDomains = map[string]string{
-	"yandex.com": "213.180.193.56",
-	"yandex.ru":  "213.180.193.56",
-	"yandex.ua":  "213.180.193.56",
-	"yandex.by":  "213.180.193.56",
-	"yandex.kz":  "213.180.193.56",
+	"yandex.com":     "213.180.193.56",
+	"yandex.ru":      "213.180.193.56",
+	"yandex.ua":      "213.180.193.56",
+	"yandex.by":      "213.180.193.56",
+	"yandex.kz":      "213.180.193.56",
 	"www.yandex.com": "213.180.193.56",
 	"www.yandex.ru":  "213.180.193.56",
 	"www.yandex.ua":  "213.180.193.56",
diff --git a/dnsforward/dnsforward_test.go b/dnsforward/dnsforward_test.go
index df14b8ae..c068d0ef 100644
--- a/dnsforward/dnsforward_test.go
+++ b/dnsforward/dnsforward_test.go
@@ -157,7 +157,7 @@ func TestSafeSearch(t *testing.T) {
 	client := dns.Client{Net: "udp"}
 	yandexDomains := []string{"yandex.com.", "yandex.by.", "yandex.kz.", "yandex.ru.", "yandex.com."}
 	for _, host := range yandexDomains {
-		exchangeAndAssertResponse(t, client, addr, host, "213.180.193.56")
+		exchangeAndAssertResponse(t, &client, addr, host, "213.180.193.56")
 	}
 
 	// Check aggregated stats
@@ -182,7 +182,7 @@ func TestSafeSearch(t *testing.T) {
 	// Test safe search for google.
 	googleDomains := []string{"www.google.com.", "www.google.com.af.", "www.google.be.", "www.google.by."}
 	for _, host := range googleDomains {
-		exchangeAndAssertResponse(t, client, addr, host, ip.String())
+		exchangeAndAssertResponse(t, &client, addr, host, ip.String())
 	}
 
 	// Check aggregated stats
@@ -191,7 +191,7 @@ func TestSafeSearch(t *testing.T) {
 	assert.Equal(t, s.GetAggregatedStats()["dns_queries"], float64(len(yandexDomains)+len(googleDomains)))
 
 	// Do one more exchange
-	exchangeAndAssertResponse(t, client, addr, "google-public-dns-a.google.com.", "8.8.8.8")
+	exchangeAndAssertResponse(t, &client, addr, "google-public-dns-a.google.com.", "8.8.8.8")
 
 	// Check aggregated stats
 	assert.Equal(t, s.GetAggregatedStats()["replaced_safesearch"], float64(len(yandexDomains)+len(googleDomains)))
@@ -524,7 +524,7 @@ func sendTestMessages(t *testing.T, conn *dns.Conn) {
 	}
 }
 
-func exchangeAndAssertResponse(t *testing.T, client dns.Client, addr net.Addr, host, ip string) {
+func exchangeAndAssertResponse(t *testing.T, client *dns.Client, addr net.Addr, host, ip string) {
 	req := createTestMessage(host)
 	reply, _, err := client.Exchange(req, addr.String())
 	if err != nil {
diff --git a/dnsforward/stats.go b/dnsforward/stats.go
index 705a250f..62565a98 100644
--- a/dnsforward/stats.go
+++ b/dnsforward/stats.go
@@ -61,9 +61,11 @@ func newStats() *stats {
 }
 
 func initPeriodicStats(periodic *periodicStats, period time.Duration) {
+	periodic.Lock()
 	periodic.entries = statsEntries{}
 	periodic.lastRotate = time.Now()
 	periodic.period = period
+	periodic.Unlock()
 }
 
 func (s *stats) purgeStats() {
@@ -253,6 +255,9 @@ func (s *stats) getAggregatedStats() map[string]interface{} {
 }
 
 func (s *stats) generateMapFromStats(stats *periodicStats, start int, end int) map[string]interface{} {
+	stats.RLock()
+	defer stats.RUnlock()
+
 	// clamp
 	start = clamp(start, 0, statsHistoryElements)
 	end = clamp(end, 0, statsHistoryElements)