diff --git a/sanitizers/src/main/java/com/code_intelligence/jazzer/sanitizers/Utils.kt b/sanitizers/src/main/java/com/code_intelligence/jazzer/sanitizers/Utils.kt
index 9a6c97fc7..0a1ba3b4a 100644
--- a/sanitizers/src/main/java/com/code_intelligence/jazzer/sanitizers/Utils.kt
+++ b/sanitizers/src/main/java/com/code_intelligence/jazzer/sanitizers/Utils.kt
@@ -59,7 +59,7 @@ internal fun peekMarkableInputStream(
             if (count < 0) break
             n += count
         }
-        return if (n >= readlimit) current else current.copyOf(n)
+        return if (n < size) current.copyOf(n) else current
     }
     check(stream.markSupported())
     stream.mark(readlimit)