src/jdk.internal.vm.compiler/share/classes/org.graalvm.graphio/src/org/graalvm/graphio/GraphProtocol.java

@@ -525,11 +525,11 @@
             ResolvedJavaMethod method = findNodeSourcePositionMethod(pos);
             writePoolObject(method);
             final int bci = findNodeSourcePositionBCI(pos);
             writeInt(bci);
             StackTraceElement ste = findMethodStackTraceElement(method, bci, pos);
-            if (ste != null) {
+            if (ste != null && ste.getFileName() != null) {
                 writePoolObject(ste.getFileName());
                 writeInt(ste.getLineNumber());
             } else {
                 writePoolObject(null);
             }