Avoid suspending heap task thread for getting stack traces
Instead of suspending the heap task thread, GetThreadStack (called by
VMStack_fillStackTraceElements and VMStack_getThreadStackTrace) will
return an empty thread stack. This fixes possible deadlocks caused by
suspending the GC thread and doing allocations for the stack trace.
Bug: 28261069
Test: test-art-host
Change-Id: I45a0b8ac94a99d6bbcfcdc2b41afadf941ec0138
diff --git a/test/129-ThreadGetId/src/Main.java b/test/129-ThreadGetId/src/Main.java
index 9934bba..5aefd17 100644
--- a/test/129-ThreadGetId/src/Main.java
+++ b/test/129-ThreadGetId/src/Main.java
@@ -22,6 +22,7 @@
public static void main(String[] args) throws Exception {
final Thread[] threads = new Thread[numberOfThreads];
+ test_getStackTraces();
for (int t = 0; t < threads.length; t++) {
threads[t] = new Thread(new Main());
threads[t].start();
@@ -32,6 +33,19 @@
System.out.println("Finishing");
}
+ static void test_getStackTraces() {
+ // Check all the current threads for positive IDs.
+ Map<Thread, StackTraceElement[]> map = Thread.getAllStackTraces();
+ for (Map.Entry<Thread, StackTraceElement[]> pair : map.entrySet()) {
+ Thread thread = pair.getKey();
+ // Expect empty stack trace since we do not support suspending the GC thread for
+ // obtaining stack traces. See b/28261069.
+ if (thread.getName().equals("HeapTaskDaemon")) {
+ System.out.println(thread.getName() + " depth " + pair.getValue().length);
+ }
+ }
+ }
+
public void test_getId() {
if (Thread.currentThread().getId() <= 0) {
System.out.println("current thread's ID is not positive");