# HG changeset patch
# User qpzhang <patrick@os.amperecomputing.com>
# Date 1555048701 -28800
#      Fri Apr 12 13:58:21 2019 +0800
# Node ID a8fcb3f9622fd82ef157edf783a54491b93da30f
# Parent  f22759e921912832518134af9ee50d4b3a3e7c7f
8222334: java -Xss0 triggers StackOverflowError
Summary: Launcher to use the ThreadStackSize decided by hotpot or system if input is 0
Reviewed-by: dholmes

diff --git a/src/java.base/share/native/libjli/java.c b/src/java.base/share/native/libjli/java.c
--- a/src/java.base/share/native/libjli/java.c
+++ b/src/java.base/share/native/libjli/java.c
@@ -942,8 +942,13 @@
              * Make sure the thread stack size is big enough that we won't get a stack
              * overflow before the JVM startup code can check to make sure the stack
              * is big enough.
+             * If the input thread stack size is 0, try to ask HotSpot to determine
+             * a proper value later when creating thread for JavaMain, or use the
+             * system default stack size. VM would create inner threads using its
+             * calculated sizes, forced STACK_SIZE_MINIMUM here may trigger
+             * StackOverflowError in HotSpot. See JDK-8222334 for details.
              */
-            if (threadStackSize < (jlong)STACK_SIZE_MINIMUM) {
+            if (threadStackSize != 0 && threadStackSize < (jlong)STACK_SIZE_MINIMUM) {
                 threadStackSize = STACK_SIZE_MINIMUM;
             }
         }
@@ -2334,7 +2339,13 @@
       args1_1.version = JNI_VERSION_1_1;
       ifn->GetDefaultJavaVMInitArgs(&args1_1);  /* ignore return value */
       if (args1_1.javaStackSize > 0) {
-         threadStackSize = args1_1.javaStackSize;
+        threadStackSize = args1_1.javaStackSize;
+      } else {
+        /*
+         * pthread_create would use system default stack size, e.g.,
+         * ulimit -s shows:
+         * stack size (kbytes, -s) 8192
+         */
       }
     }