Free all native object stubs in lookup table at context finalization

Author: fangerer

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/cext/capi/CApiContext.java

@@ -80,6 +80,7 @@
 import com.oracle.graal.python.builtins.objects.cext.capi.transitions.CApiTransitions;
 import com.oracle.graal.python.builtins.objects.cext.capi.transitions.CApiTransitions.HandleContext;
 import com.oracle.graal.python.builtins.objects.cext.capi.transitions.CApiTransitions.NativeToPythonNode;
+import com.oracle.graal.python.builtins.objects.cext.capi.transitions.CApiTransitions.PythonObjectReference;
 import com.oracle.graal.python.builtins.objects.cext.capi.transitions.CApiTransitions.ToPythonWrapperNode;
 import com.oracle.graal.python.builtins.objects.cext.common.CExtCommonNodes.CheckFunctionResultNode;
 import com.oracle.graal.python.builtins.objects.cext.common.CExtContext;
@@ -875,16 +876,28 @@ public void finalizeCapi() {
         CApiTransitions.disableReferenceQueuePolling(getContext().nativeContext);
         // TODO(fa): remove GIL acquisition (GR-51314)
         try (GilNode.UncachedAcquire gil = GilNode.uncachedAcquire()) {
+            HandleContext nativeContext = getContext().nativeContext;
             freeSmallInts();
             for (int i = 0; i < singletonNativePtrs.length; i++) {
                 PythonNativeWrapper singletonNativeWrapper = singletonNativePtrs[i];
                 singletonNativePtrs[i] = null;
                 assert singletonNativeWrapper != null;
                 if (singletonNativeWrapper.ref != null) {
-                    CApiTransitions.nativeStubLookupRemove(getContext().nativeContext, singletonNativeWrapper.ref);
+                    CApiTransitions.nativeStubLookupRemove(nativeContext, singletonNativeWrapper.ref);
                 }
                 PyTruffleObjectFree.releaseNativeWrapperUncached(singletonNativeWrapper);
             }
+            /*
+             * Clear all remaining native object stubs. This must be done after the small int and
+             * the singleton wrappers were cleared because they might also end up in the lookup
+             * table and may otherwise be double-free'd.
+             */
+            for (PythonObjectReference ref : nativeContext.nativeStubLookup) {
+                if (ref != null) {
+                    CApiTransitions.nativeStubLookupRemove(nativeContext, ref);
+                    CApiTransitions.freeNativeStub(ref);
+                }
+            }
         }
         if (pyDateTimeCAPICapsule != null) {
             PyDateTimeCAPIWrapper.destroyWrapper(pyDateTimeCAPICapsule);

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/cext/capi/transitions/CApiTransitions.java

@@ -383,8 +383,7 @@ public static void pollReferenceQueue() {
                              */
                             long stubPointer = HandlePointerConverter.pointerToStub(reference.pointer);
                             if (subNativeRefCount(stubPointer, PythonAbstractObjectNativeWrapper.MANAGED_REFCNT) == 0) {
-                                LOGGER.fine(() -> PythonUtils.formatJString("freeing native object stub 0x%x", stubPointer));
-                                FreeNode.executeUncached(stubPointer);
+                                freeNativeStub(stubPointer);
                             } else {
                                 /*
                                  * In this case, the object is no longer referenced from managed but
@@ -422,6 +421,20 @@ public static void disableReferenceQueuePolling(HandleContext handleContext) {
         handleContext.referenceQueuePollActive = true;
     }
 
+    public static boolean isReferenceQueuePollingDisabled(HandleContext handleContext) {
+        return handleContext.referenceQueuePollActive;
+    }
+
+    private static void freeNativeStub(long stubPointer) {
+        LOGGER.fine(() -> PythonUtils.formatJString("freeing native object stub 0x%x", stubPointer));
+        FreeNode.executeUncached(stubPointer);
+    }
+
+    public static void freeNativeStub(PythonObjectReference ref) {
+        assert HandlePointerConverter.pointsToPyHandleSpace(ref.pointer);
+        freeNativeStub(HandlePointerConverter.pointerToStub(ref.pointer));
+    }
+
     /**
      * We need to call __dealloc__ for native weakref objects before exit, as some objects might
      * need to use capi functions.