Ignore crashed threads.

Author: christianhaeubl

substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/GCImpl.java

@@ -865,6 +865,10 @@ private void blackenStackRoots() {
                          */
                         continue;
                     }
+                    if (VMThreads.SafepointBehavior.isCrashedThread(vmThread)) {
+                        /* The Java frame anchors or the values on the stack may be corrupt. */
+                        continue;
+                    }
                     if (JavaStackWalker.initWalk(walk, vmThread)) {
                         walkStack(walk);
                     }

substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/StackVerifier.java

@@ -61,6 +61,10 @@ public static boolean verifyAllThreads() {
                 if (vmThread == CurrentIsolate.getCurrentThread()) {
                     continue;
                 }
+                if (VMThreads.SafepointBehavior.isCrashedThread(vmThread)) {
+                    /* The Java frame anchors or the values on the stack may be corrupt. */
+                    continue;
+                }
                 JavaStackWalker.walkThread(vmThread, STACK_FRAME_VISITOR);
             }
         }

substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/ThreadLocalAllocation.java

@@ -418,6 +418,10 @@ static void disableAndFlushForAllThreads() {
 
         if (SubstrateOptions.MultiThreaded.getValue()) {
             for (IsolateThread vmThread = VMThreads.firstThread(); vmThread.isNonNull(); vmThread = VMThreads.nextThread(vmThread)) {
+                if (VMThreads.SafepointBehavior.isCrashedThread(vmThread)) {
+                    /* Ignore crashed threads because the TLAB can be corrupt. */
+                    continue;
+                }
                 disableAndFlushForThread(vmThread);
             }
         } else {

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/DumpThreadStacksOnSignalFeature.java

@@ -92,6 +92,10 @@ protected void operate() {
                     /* Skip the signal handler stack */
                     continue;
                 }
+                if (VMThreads.SafepointBehavior.isCrashedThread(vmThread)) {
+                    /* The Java frame anchors or the values on the stack may be corrupt. */
+                    continue;
+                }
                 try {
                     dumpStack(log, vmThread);
                 } catch (Exception e) {

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/SubstrateDiagnostics.java

@@ -906,6 +906,10 @@ public void printDiagnostics(Log log, ErrorContext context, int maxDiagnosticLev
                     if (vmThread == CurrentIsolate.getCurrentThread()) {
                         continue;
                     }
+                    if (VMThreads.SafepointBehavior.isCrashedThread(vmThread)) {
+                        /* The Java frame anchors or the values on the stack may be corrupt. */
+                        continue;
+                    }
                     if (printed >= MAX_THREADS_TO_PRINT) {
                         log.string("... (truncated)").newline();
                         break;

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/code/RuntimeCodeCache.java

@@ -302,6 +302,10 @@ public boolean verify(CodeInfo info) {
                     if (vmThread == CurrentIsolate.getCurrentThread()) {
                         continue;
                     }
+                    if (VMThreads.SafepointBehavior.isCrashedThread(vmThread)) {
+                        /* The Java frame anchors or the values on the stack may be corrupt. */
+                        continue;
+                    }
                     JavaStackWalker.walkThread(vmThread, this);
                 }
             }

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/deopt/Deoptimizer.java

@@ -306,6 +306,10 @@ private static void deoptimizeInRangeOperation(CodePointer fromIp, CodePointer t
                 if (vmThread == CurrentIsolate.getCurrentThread()) {
                     continue;
                 }
+                if (VMThreads.SafepointBehavior.isCrashedThread(vmThread)) {
+                    /* The Java frame anchors or the values on the stack may be corrupt. */
+                    continue;
+                }
                 StackFrameVisitor deoptVisitor = getStackFrameVisitor((Pointer) fromIp, (Pointer) toIp, deoptAll, vmThread);
                 JavaStackWalker.walkThread(vmThread, deoptVisitor);
             }

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/thread/PlatformThreads.java

@@ -1037,6 +1037,11 @@ private static class GetAllThreadsOperation extends JavaVMOperation {
         @Override
         protected void operate() {
             for (IsolateThread cur = VMThreads.firstThread(); cur.isNonNull(); cur = VMThreads.nextThread(cur)) {
+                if (VMThreads.SafepointBehavior.isCrashedThread(cur)) {
+                    /* The Java frame anchors or the values on the stack may be corrupt. */
+                    continue;
+                }
+
                 Thread thread = PlatformThreads.fromVMThread(cur);
                 if (thread != null) {
                     result.add(thread);

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/thread/VMThreads.java

@@ -866,13 +866,11 @@ public static int getSafepointBehaviorVolatile(IsolateThread vmThread) {
          * thread status).
          * 
          * NOTE: Be careful with this method and make sure that this thread does not allocate any
-         * Java objects as this could result deadlocks. This method will only work prevent
-         * safepoints reliably if it is called from a thread with
-         * {@link StatusSupport#STATUS_IN_JAVA}.
+         * Java objects as this could result deadlocks. This method will only prevent safepoints
+         * reliably if it is called from a thread with {@link StatusSupport#STATUS_IN_JAVA}.
          */
         @Uninterruptible(reason = "Called from uninterruptible code.", callerMustBe = true)
         public static void preventSafepoints() {
-            // It would be nice if we could retire the TLAB here but that wouldn't work reliably.
             safepointBehaviorTL.setVolatile(PREVENT_VM_FROM_REACHING_SAFEPOINT);
         }
 
@@ -895,6 +893,11 @@ public static void markThreadAsCrashed() {
             safepointBehaviorTL.setVolatile(THREAD_CRASHED);
         }
 
+        @Uninterruptible(reason = "Called from uninterruptible code.", mayBeInlined = true)
+        public static boolean isCrashedThread(IsolateThread thread) {
+            return safepointBehaviorTL.getVolatile(thread) == THREAD_CRASHED;
+        }
+
         @Uninterruptible(reason = "Called from uninterruptible code.", mayBeInlined = true)
         public static String toString(int safepointBehavior) {
             switch (safepointBehavior) {