Return NULL from getStackTraceForThread for unsteady virtual threads

If inspectorCount is -1, then the virtual thread is in an unsteady state (mounting or unmounting). In such cases, NULL should be returned and the JCL code should retry in order to avoid unexpected behavior. Related: eclipse-openj9#18910 Signed-off-by: Babneet Singh <[email protected]>
babsingh · Oct 4, 2024 · 5ff75a3 · 5ff75a3
1 parent 845b1ce
commit 5ff75a3
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/runtime/jcl/common/getstacktrace.c b/runtime/jcl/common/getstacktrace.c
@@ -80,7 +80,10 @@ getStackTraceForThread(J9VMThread *currentThread, J9VMThread *targetThread, UDAT
 		 */
 		walkState.skipCount = 0;
 		rc = vmfns->walkContinuationStackFrames(currentThread, targetThread->currentContinuation, threadObject, &walkState);
-	} else if (isVirtual && (threadObject != targetThread->threadObject)) {
+	} else if (isVirtual
+	&& ((threadObject != targetThread->threadObject)
+		|| (-1 == J9OBJECT_I64_LOAD(currentThread, threadObject, vm->virtualThreadInspectorCountOffset)))
+	) {
 		/* If the virtual thread object doesn't match the current thread object, it must have unmounted
 		 * from this carrier thread, return NULL and the JCL code will handle the retry.
 		 */