[GR-39701] Ignore crashed threads.

PullRequest: graal/15829
zakkak · Oct 31, 2023 · 9e8106b · 9e8106b
2 parents 97a8bb6 + bf9b6b2
commit 9e8106b
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Showing 3 changed files with 13 additions and 37 deletions.
diff --git a/substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/stack/JavaStackWalker.java b/substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/stack/JavaStackWalker.java
@@ -45,6 +45,7 @@
 import com.oracle.svm.core.heap.RestrictHeapAccess;
 import com.oracle.svm.core.log.Log;
 import com.oracle.svm.core.thread.VMOperation;
+import com.oracle.svm.core.thread.VMThreads.SafepointBehavior;
 import com.oracle.svm.core.util.VMError;
 
 /**
@@ -134,6 +135,11 @@ public static boolean initWalk(JavaStackWalk walk, IsolateThread thread) {
         assert thread.notEqual(CurrentIsolate.getCurrentThread()) : "Cannot walk the current stack with this method, it would miss all frames after the last frame anchor";
         assert VMOperation.isInProgressAtSafepoint() : "Walking the stack of another thread is only safe when that thread is stopped at a safepoint";
 
+        if (SafepointBehavior.isCrashedThread(thread)) {
+            /* Skip crashed threads because they may no longer have a stack. */
+            return false;
+        }
+
         JavaFrameAnchor anchor = JavaFrameAnchors.getFrameAnchor(thread);
         boolean result = anchor.isNonNull();
         Pointer sp = WordFactory.nullPointer();

diff --git a/substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/thread/Safepoint.java b/substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/thread/Safepoint.java
@@ -876,42 +876,7 @@ public UnsignedWord getSafepointId() {
             return safepointId;
         }
 
-        /** A sample method to execute in a VMOperation. */
         public static class TestingBackdoor {
-
-            public static int countingVMOperation() {
-                final Log trace = Log.log().string("[Safepoint.Master.TestingBackdoor.countingVMOperation:").newline();
-                int atSafepoint = 0;
-                int ignoreSafepoints = 0;
-                int notAtSafepoint = 0;
-
-                for (IsolateThread vmThread = VMThreads.firstThread(); vmThread.isNonNull(); vmThread = VMThreads.nextThread(vmThread)) {
-                    int safepointBehavior = SafepointBehavior.getSafepointBehaviorVolatile(vmThread);
-                    int status = StatusSupport.getStatusVolatile(vmThread);
-                    if (safepointBehavior == SafepointBehavior.PREVENT_VM_FROM_REACHING_SAFEPOINT) {
-                        notAtSafepoint++;
-                    } else if (safepointBehavior == SafepointBehavior.THREAD_CRASHED) {
-                        ignoreSafepoints += 1;
-                    } else {
-                        assert safepointBehavior == SafepointBehavior.ALLOW_SAFEPOINT;
-                        // Check if the thread is at a safepoint or in native code.
-                        switch (status) {
-                            case StatusSupport.STATUS_IN_SAFEPOINT:
-                                atSafepoint += 1;
-                                break;
-                            default:
-                                notAtSafepoint += 1;
-                                break;
-                        }
-                    }
-                }
-                trace.string("  atSafepoint: ").signed(atSafepoint)
-                                .string("  ignoreSafepoints: ").signed(ignoreSafepoints)
-                                .string("  notAtSafepoint: ").signed(notAtSafepoint);
-                trace.string("]").newline();
-                return atSafepoint;
-            }
-
             @Uninterruptible(reason = "Called from uninterruptible code.", mayBeInlined = true)
             public static int getCurrentThreadSafepointRequestedCount() {
                 return getSafepointRequested(CurrentIsolate.getCurrentThread());

diff --git a/substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/thread/VMThreads.java b/substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/thread/VMThreads.java
@@ -888,13 +888,13 @@ public static class SafepointBehavior {
          * The thread won't freeze at a safepoint, and will actively prevent the VM from reaching a
          * safepoint (regardless of the thread status).
          */
-        static final int PREVENT_VM_FROM_REACHING_SAFEPOINT = 1;
+        public static final int PREVENT_VM_FROM_REACHING_SAFEPOINT = 1;
 
         /**
          * The thread won't freeze at a safepoint and the safepoint handling will ignore the thread.
          * So, the VM will be able to reach a safepoint regardless of the status of this thread.
          */
-        static final int THREAD_CRASHED = 2;
+        public static final int THREAD_CRASHED = 2;
 
         @Uninterruptible(reason = "Called from uninterruptible code.", mayBeInlined = true)
         public static boolean ignoresSafepoints() {
@@ -945,6 +945,11 @@ 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) {