diff --git a/src/banman.cpp b/src/banman.cpp
index 7fa489b0514..2b029198db3 100644
--- a/src/banman.cpp
+++ b/src/banman.cpp
@@ -43,9 +43,11 @@ void BanMan::DumpBanlist()
     static Mutex dump_mutex;
     LOCK(dump_mutex);
 
-    SweepBanned(); // clean unused entries (if bantime has expired)
-
-    if (!BannedSetIsDirty()) return;
+    {
+        LOCK(m_cs_banned);
+        SweepBanned();
+        if (!BannedSetIsDirty()) return;
+    }
 
     int64_t n_start = GetTimeMillis();