changeset 28102:0efebd8c99e2

6762191: Setting stack size to 16K causes segmentation fault Summary: Fixed by forcing the stack size to always be at least 32k. Reviewed-by: dholmes, alanb, ksrini, sspitsyn
author cjplummer
date Thu, 04 Dec 2014 11:26:46 -0800
parents acc6f4bcb37e
children 7e1de7f8a5b9
files jdk/src/java.base/share/native/libjli/java.c jdk/test/tools/launcher/TooSmallStackSize.java
diffstat 2 files changed, 173 insertions(+), 0 deletions(-) [+]
line wrap: on
line diff
--- a/jdk/src/java.base/share/native/libjli/java.c	Wed Dec 03 16:44:35 2014 +0100
+++ b/jdk/src/java.base/share/native/libjli/java.c	Thu Dec 04 11:26:46 2014 -0800
@@ -169,6 +169,13 @@
 static jlong initialHeapSize    = 0;  /* inital heap size */
 
 /*
+ * A minimum -Xss stack size suitable for all platforms.
+ */
+#ifndef STACK_SIZE_MINIMUM
+#define STACK_SIZE_MINIMUM (32 * KB)
+#endif
+
+/*
  * Entry point.
  */
 int
@@ -773,6 +780,14 @@
         jlong tmp;
         if (parse_size(str + 4, &tmp)) {
             threadStackSize = tmp;
+            /*
+             * 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 (threadStackSize < STACK_SIZE_MINIMUM) {
+                threadStackSize = STACK_SIZE_MINIMUM;
+            }
         }
     }
 
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/tools/launcher/TooSmallStackSize.java	Thu Dec 04 11:26:46 2014 -0800
@@ -0,0 +1,158 @@
+/*
+ * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 6762191
+ * @summary Setting stack size to 16K causes segmentation fault
+ * @compile TooSmallStackSize.java
+ * @run main TooSmallStackSize
+ */
+
+/*
+ * The primary purpose of this test is to make sure we can run with a 16k stack
+ * size without crashing. Also this test will determine the minimum allowed
+ * stack size for the platform (as provided by the JVM error message when a very
+ * small stack is used), and then verify that the JVM can be launched with that stack
+ * size without a crash or any error messages.
+ */
+
+public class TooSmallStackSize extends TestHelper {
+    /* for debugging. Normally false. */
+    static final boolean verbose = false;
+
+    static void printTestOutput(TestResult tr) {
+        System.out.println("*** exitValue = " + tr.exitValue);
+        for (String x : tr.testOutput) {
+            System.out.println(x);
+        }
+    }
+
+    /*
+     * Returns the minimum stack size this platform will allowed based on the
+     * contents of the error message the JVM outputs when too small of a
+     * -Xss size was used.
+     *
+     * The TestResult argument must contain the result of having already run
+     * the JVM with too small of a stack size.
+     */
+    static String getMinStackAllowed(TestResult tr) {
+        /*
+         * The JVM output will contain in one of the lines:
+         *   "The stack size specified is too small, Specify at least 100k"
+         * Although the actual size will vary. We need to extract this size
+         * string from the output and return it.
+         */
+        String matchStr = "Specify at least ";
+        for (String x : tr.testOutput) {
+            int match_idx = x.indexOf(matchStr);
+            if (match_idx >= 0) {
+                int size_start_idx = match_idx + matchStr.length();
+                int k_start_idx = x.indexOf("k", size_start_idx);
+                return x.substring(size_start_idx, k_start_idx + 1); // include the "k"
+            }
+        }
+
+        System.out.println("FAILED: Could not get the stack size from the output");
+        throw new RuntimeException("test fails");
+    }
+
+    /*
+     * Run the JVM with the specified stack size.
+     *
+     * Returns the minimum allowed stack size gleaned from the error message,
+     * if there is an error message. Otherwise returns the stack size passed in.
+     */
+    static String checkStack(String stackSize) {
+        String min_stack_allowed;
+        TestResult tr;
+
+        if (verbose)
+            System.out.println("*** Testing " + stackSize);
+        tr = doExec(javaCmd, "-Xss" + stackSize, "-version");
+        if (verbose)
+            printTestOutput(tr);
+
+        if (tr.isOK()) {
+            System.out.println("PASSED: got no error message with stack size of " + stackSize);
+            min_stack_allowed = stackSize;
+        } else {
+            if (tr.contains("The stack size specified is too small")) {
+                System.out.println("PASSED: got expected error message with stack size of " + stackSize);
+                min_stack_allowed = getMinStackAllowed(tr);
+            } else {
+                // Likely a crash
+                System.out.println("FAILED: Did not get expected error message with stack size of " + stackSize);
+                throw new RuntimeException("test fails");
+            }
+        }
+
+        return min_stack_allowed;
+    }
+
+    /*
+     * Run the JVM with the minimum allowed stack size. This should always succeed.
+     */
+    static void checkMinStackAllowed(String stackSize) {
+        TestResult tr = null;
+
+        if (verbose)
+            System.out.println("*** Testing " + stackSize);
+        tr = doExec(javaCmd, "-Xss" + stackSize, "-version");
+        if (verbose)
+            printTestOutput(tr);
+
+        if (tr.isOK()) {
+            System.out.println("PASSED: VM launched with minimum allowed stack size of " + stackSize);
+        } else {
+            // Likely a crash
+            System.out.println("FAILED: VM failed to launch with minimum allowed stack size of " + stackSize);
+            throw new RuntimeException("test fails");
+        }
+    }
+
+    public static void main(String... args) {
+        /*
+         * The result of a 16k stack size should be a quick exit with a complaint
+         * that the stack size is too small. However, for some win32 builds, the
+         * stack is always at least 64k, and this also sometimes is the minimum
+         * allowed size, so we won't see an error in this case.
+         *
+         * This test case will also produce a crash on some platforms if the fix
+         * for 6762191 is not yet in place.
+         */
+        checkStack("16k");
+
+        /*
+         * Try with a 32k stack size, which is the size that the launcher will
+         * set to if you try setting to anything smaller. This should produce the same
+         * result as setting to 16k if the fix for 6762191 is in place.
+         */
+        String min_stack_allowed = checkStack("32k");
+
+        /*
+         * Try again with a the minimum stack size that was given in the error message
+         */
+        checkMinStackAllowed(min_stack_allowed);
+    }
+}