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8258836: JNI local refs exceed capacity getDiagnosticCommandInfo
Reviewed-by: cjplummer, shade
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jerboaa committed Jan 25, 2021
1 parent d825339 commit af155fc06863339660993e05a5e6737046066b98
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Showing 2 changed files with 137 additions and 23 deletions.
@@ -1,5 +1,5 @@
/*
* Copyright (c) 2013, 2016, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2013, 2021, 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
@@ -45,12 +45,21 @@ Java_com_sun_management_internal_DiagnosticCommandImpl_getDiagnosticCommands
return jmm_interface->GetDiagnosticCommands(env);
}

#define EXCEPTION_CHECK_AND_FREE(x) do { \
if ((*env)->ExceptionCheck(env)) { \
free(x); \
return NULL; \
} \
} while(0)
//
// Checks for an exception and if one occurred,
// pops 'pops' local frames and frees 'x' before
// returning NULL
//
#define POP_EXCEPTION_CHECK_AND_FREE(pops, x) do { \
if ((*env)->ExceptionCheck(env)) { \
int i; \
for (i = 0; i < pops; i++) { \
(*env)->PopLocalFrame(env, NULL); \
} \
free(x); \
return NULL; \
} \
} while(0)

jobject getDiagnosticCommandArgumentInfoArray(JNIEnv *env, jstring command,
int num_arg) {
@@ -73,30 +82,29 @@ jobject getDiagnosticCommandArgumentInfoArray(JNIEnv *env, jstring command,
dcmd_arg_info_array);
dcmdArgInfoCls = (*env)->FindClass(env,
"com/sun/management/internal/DiagnosticCommandArgumentInfo");
if ((*env)->ExceptionCheck(env)) {
free(dcmd_arg_info_array);
return NULL;
}
POP_EXCEPTION_CHECK_AND_FREE(0, dcmd_arg_info_array);

result = (*env)->NewObjectArray(env, num_arg, dcmdArgInfoCls, NULL);
if (result == NULL) {
free(dcmd_arg_info_array);
return NULL;
}
for (i=0; i<num_arg; i++) {
jstring jname, jdesc,jtype,jdefStr;
// Capacity for 5 local refs: jname, jdesc, jtype, jdefStr and obj
(*env)->PushLocalFrame(env, 5);
jstring jname, jdesc, jtype, jdefStr;

jname = (*env)->NewStringUTF(env,dcmd_arg_info_array[i].name);
EXCEPTION_CHECK_AND_FREE(dcmd_arg_info_array);
POP_EXCEPTION_CHECK_AND_FREE(1, dcmd_arg_info_array);

jdesc = (*env)->NewStringUTF(env,dcmd_arg_info_array[i].description);
EXCEPTION_CHECK_AND_FREE(dcmd_arg_info_array);
POP_EXCEPTION_CHECK_AND_FREE(1, dcmd_arg_info_array);

jtype = (*env)->NewStringUTF(env,dcmd_arg_info_array[i].type);
EXCEPTION_CHECK_AND_FREE(dcmd_arg_info_array);
POP_EXCEPTION_CHECK_AND_FREE(1, dcmd_arg_info_array);

jdefStr = (*env)->NewStringUTF(env, dcmd_arg_info_array[i].default_string);
EXCEPTION_CHECK_AND_FREE(dcmd_arg_info_array);
POP_EXCEPTION_CHECK_AND_FREE(1, dcmd_arg_info_array);
obj = JNU_NewObjectByName(env,
"com/sun/management/internal/DiagnosticCommandArgumentInfo",
"(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;ZZZI)V",
@@ -107,11 +115,13 @@ jobject getDiagnosticCommandArgumentInfoArray(JNIEnv *env, jstring command,
dcmd_arg_info_array[i].multiple,
dcmd_arg_info_array[i].position);
if (obj == NULL) {
(*env)->PopLocalFrame(env, NULL);
free(dcmd_arg_info_array);
return NULL;
}
obj = (*env)->PopLocalFrame(env, obj);
(*env)->SetObjectArrayElement(env, result, i, obj);
EXCEPTION_CHECK_AND_FREE(dcmd_arg_info_array);
POP_EXCEPTION_CHECK_AND_FREE(0, dcmd_arg_info_array);
}
free(dcmd_arg_info_array);
arraysCls = (*env)->FindClass(env, "java/util/Arrays");
@@ -144,51 +154,67 @@ Java_com_sun_management_internal_DiagnosticCommandImpl_getDiagnosticCommandInfo
jint ret = jmm_interface->GetOptionalSupport(env, &mos);
jsize num_commands;
dcmdInfo* dcmd_info_array;
jstring jname, jdesc, jimpact;
jstring jname, jdesc, jimpact, cmd;

if (commands == NULL) {
JNU_ThrowNullPointerException(env, "Invalid String Array");
return NULL;
}
num_commands = (*env)->GetArrayLength(env, commands);
// Ensure capacity for 2 + num_commands local refs:
// 2 => dcmdInfoCls, result
// num_commmands => one obj per command
(*env)->PushLocalFrame(env, 2 + num_commands);
dcmdInfoCls = (*env)->FindClass(env,
"com/sun/management/internal/DiagnosticCommandInfo");
if ((*env)->ExceptionCheck(env)) {
(*env)->PopLocalFrame(env, NULL);
return NULL;
}

result = (*env)->NewObjectArray(env, num_commands, dcmdInfoCls, NULL);
if (result == NULL) {
(*env)->PopLocalFrame(env, NULL);
return NULL;
}
if (num_commands == 0) {
result = (*env)->PopLocalFrame(env, result);
/* Handle the 'zero commands' case specially to avoid calling 'malloc()' */
/* with a zero argument because that may legally return a NULL pointer. */
return result;
}
dcmd_info_array = (dcmdInfo*) malloc(num_commands * sizeof(dcmdInfo));
if (dcmd_info_array == NULL) {
(*env)->PopLocalFrame(env, NULL);
JNU_ThrowOutOfMemoryError(env, NULL);
return NULL;
}
jmm_interface->GetDiagnosticCommandInfo(env, commands, dcmd_info_array);
for (i=0; i<num_commands; i++) {
// Ensure capacity for 6 + 3 local refs:
// 6 => jname, jdesc, jimpact, cmd, args, obj
// 3 => permission class, name, action
(*env)->PushLocalFrame(env, 6 + 3);

cmd = (*env)->GetObjectArrayElement(env, commands, i);
args = getDiagnosticCommandArgumentInfoArray(env,
(*env)->GetObjectArrayElement(env,commands,i),
cmd,
dcmd_info_array[i].num_arguments);
if (args == NULL) {
(*env)->PopLocalFrame(env, NULL);
(*env)->PopLocalFrame(env, NULL);
free(dcmd_info_array);
return NULL;
}

jname = (*env)->NewStringUTF(env,dcmd_info_array[i].name);
EXCEPTION_CHECK_AND_FREE(dcmd_info_array);
POP_EXCEPTION_CHECK_AND_FREE(2, dcmd_info_array);

jdesc = (*env)->NewStringUTF(env,dcmd_info_array[i].description);
EXCEPTION_CHECK_AND_FREE(dcmd_info_array);
POP_EXCEPTION_CHECK_AND_FREE(2, dcmd_info_array);

jimpact = (*env)->NewStringUTF(env,dcmd_info_array[i].impact);
EXCEPTION_CHECK_AND_FREE(dcmd_info_array);
POP_EXCEPTION_CHECK_AND_FREE(2, dcmd_info_array);

obj = JNU_NewObjectByName(env,
"com/sun/management/internal/DiagnosticCommandInfo",
@@ -200,13 +226,17 @@ Java_com_sun_management_internal_DiagnosticCommandImpl_getDiagnosticCommandInfo
dcmd_info_array[i].enabled,
args);
if (obj == NULL) {
(*env)->PopLocalFrame(env, NULL);
(*env)->PopLocalFrame(env, NULL);
free(dcmd_info_array);
return NULL;
}
obj = (*env)->PopLocalFrame(env, obj);

(*env)->SetObjectArrayElement(env, result, i, obj);
EXCEPTION_CHECK_AND_FREE(dcmd_info_array);
POP_EXCEPTION_CHECK_AND_FREE(1, dcmd_info_array);
}
result = (*env)->PopLocalFrame(env, result);
free(dcmd_info_array);
return result;
}
@@ -0,0 +1,84 @@
/*
* Copyright (c) 2021, Red Hat, Inc.
* 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 8258836
* @summary JNI local refs exceed capacity getDiagnosticCommandInfo
* @library /test/lib
* @run main/othervm DcmdMBeanTestCheckJni
*/

import java.lang.management.ManagementFactory;
import javax.management.MBeanServer;
import javax.management.ObjectName;
import javax.management.MBeanServerConnection;
import javax.management.remote.JMXConnectorFactory;
import javax.management.remote.JMXConnector;
import javax.management.remote.JMXConnectorServerFactory;
import javax.management.remote.JMXServiceURL;
import javax.management.remote.JMXConnectorServer;

import jdk.test.lib.process.OutputAnalyzer;
import jdk.test.lib.process.ProcessTools;

public class DcmdMBeanTestCheckJni {

public static void main(String[] args) throws Exception {
OutputAnalyzer out = ProcessTools.executeTestJvm(
"-Xcheck:jni",
DcmdMBeanRunner.class.getName());
out.shouldNotMatch("WARNING: JNI local refs: \\d+, exceeds capacity: \\d+")
.shouldContain("DcmdMBeanRunner COMPLETE")
.shouldHaveExitValue(0);
}

}

class DcmdMBeanRunner {

private static final String HOTSPOT_DIAGNOSTIC_MXBEAN_NAME =
"com.sun.management:type=DiagnosticCommand";

public static void main(String[] args) throws Exception {
MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
JMXServiceURL url = new JMXServiceURL("rmi", null, 0);
JMXConnectorServer cs = null;
JMXConnector cc = null;
try {
cs = JMXConnectorServerFactory.newJMXConnectorServer(url, null, mbs);
cs.start();
JMXServiceURL addr = cs.getAddress();
cc = JMXConnectorFactory.connect(addr);
MBeanServerConnection mbsc = cc.getMBeanServerConnection();
ObjectName name = new ObjectName(HOTSPOT_DIAGNOSTIC_MXBEAN_NAME);
System.out.println("DiagnosticCommand MBean: " + name);
System.out.println("DcmdMBeanRunner COMPLETE");
} finally {
try {
cc.close();
cs.stop();
} catch (Exception e) { /* ignored */ }
}
}
}

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