1 /*
2 * Copyright (c) 2025, Red Hat, Inc.
3 * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 */
24
25 /*
26 * @test id=no_coh_no_cds
27 * @summary Test that dereferencing a Klass that is the result of a decode(0) crashes accessing the nKlass guard zone
28 * @library /test/lib
29 * @requires vm.bits == 64 & vm.debug == true & vm.flagless
30 * @requires os.family != "aix"
31 * @modules java.base/jdk.internal.misc
32 * java.management
33 * @build jdk.test.whitebox.WhiteBox
34 * @run driver jdk.test.lib.helpers.ClassFileInstaller jdk.test.whitebox.WhiteBox
35 * @run driver AccessZeroNKlassHitsProtectionZone no_coh_no_cds
36 */
37
38 /*
39 * @test id=no_coh_cds
40 * @summary Test that dereferencing a Klass that is the result of a decode(0) crashes accessing the nKlass guard zone
41 * @requires vm.cds & vm.bits == 64 & vm.debug == true & vm.flagless
42 * @requires os.family != "aix"
43 * @library /test/lib
44 * @modules java.base/jdk.internal.misc
45 * java.management
46 * @build jdk.test.whitebox.WhiteBox
47 * @run driver jdk.test.lib.helpers.ClassFileInstaller jdk.test.whitebox.WhiteBox
48 * @run driver AccessZeroNKlassHitsProtectionZone no_coh_cds
49 */
50
51 /*
52 * @test id=coh_no_cds
53 * @summary Test that dereferencing a Klass that is the result of a decode(0) crashes accessing the nKlass guard zone
54 * @requires vm.bits == 64 & vm.debug == true & vm.flagless
55 * @requires os.family != "aix"
56 * @library /test/lib
57 * @modules java.base/jdk.internal.misc
58 * java.management
59 * @build jdk.test.whitebox.WhiteBox
60 * @run driver jdk.test.lib.helpers.ClassFileInstaller jdk.test.whitebox.WhiteBox
61 * @run driver AccessZeroNKlassHitsProtectionZone coh_no_cds
62 */
63
64 /*
65 * @test id=coh_cds
66 * @summary Test that dereferencing a Klass that is the result of a decode(0) crashes accessing the nKlass guard zone
67 * @requires vm.cds & vm.bits == 64 & vm.debug == true & vm.flagless
68 * @requires os.family != "aix"
69 * @library /test/lib
70 * @modules java.base/jdk.internal.misc
71 * java.management
72 * @build jdk.test.whitebox.WhiteBox
73 * @run driver jdk.test.lib.helpers.ClassFileInstaller jdk.test.whitebox.WhiteBox
74 * @run driver AccessZeroNKlassHitsProtectionZone coh_cds
75 */
76
77 import jdk.test.lib.process.OutputAnalyzer;
78 import jdk.test.lib.process.ProcessTools;
79 import jdk.test.whitebox.WhiteBox;
80 import jtreg.SkippedException;
81
82 import java.io.File;
83 import java.io.IOException;
84 import java.util.ArrayList;
85 import java.util.regex.Pattern;
86
87 // Test that dereferencing a Klass that is the result of a narrowKlass=0 will give us immediate crashes
88 // that hit the protection zone at encoding base.
89 public class AccessZeroNKlassHitsProtectionZone {
90
91 private static OutputAnalyzer run_test(boolean COH, boolean CDS, String forceBaseString) throws IOException, SkippedException {
92 ArrayList<String> args = new ArrayList<>();
93 args.add("-Xbootclasspath/a:.");
94 args.add("-XX:+UnlockDiagnosticVMOptions");
95 args.add("-XX:+WhiteBoxAPI");
96 args.add("-XX:CompressedClassSpaceSize=128m");
97 args.add("-Xmx128m");
98 args.add("-XX:-CreateCoredumpOnCrash");
99 args.add("-Xlog:metaspace*");
100 args.add("-Xlog:cds");
101 if (COH) {
102 args.add("-XX:+UseCompactObjectHeaders");
103 }
104 if (CDS) {
105 args.add("-Xshare:on");
106 } else {
107 args.add("-Xshare:off");
108 args.add("-XX:CompressedClassSpaceBaseAddress=" + forceBaseString);
109 }
110 args.add(AccessZeroNKlassHitsProtectionZone.class.getName());
111 args.add("runwb");
112 ProcessBuilder pb = ProcessTools.createLimitedTestJavaProcessBuilder(args.toArray(new String[0]));
113
114 OutputAnalyzer output = new OutputAnalyzer(pb.start());
115 output.reportDiagnosticSummary();
116 return output;
117 }
118
119 private static void run_test(boolean COH, boolean CDS) throws IOException, SkippedException {
120 // Notes:
121 // We want to enforce zero-based encoding, to test the protection page in that case. For zero-based encoding,
122 // protection page is at address zero, no need to test that.
123 // If CDS is on, we never use zero-based, forceBase is ignored.
124 // If CDS is off, we use forceBase to (somewhat) reliably force the encoding base to beyond 32G,
125 // in order to prevent zero-based encoding. Since that may fail, we try several times.
126 OutputAnalyzer output = null;
127 long forceBase = -1;
128 if (CDS) {
129 output = run_test(COH, CDS, "");
130 // Not all distributions build COH archives. We tolerate that.
131 if (COH) {
132 String s = output.firstMatch("Specified shared archive file not found .*coh.jsa");
133 if (s != null) {
134 throw new SkippedException("Failed to find COH archive, was it not built? Skipping test.");
135 }
136 }
137 } else {
138 long g4 = 0x1_0000_0000L;
139 long start = g4 * 8; // 32g
140 long step = g4;
141 long end = start + step * 16;
142 for (forceBase = start; forceBase < end; forceBase += step) {
143 String thisBaseString = String.format("0x%016X", forceBase).toLowerCase();
144 output = run_test(COH, CDS, thisBaseString);
145 if (output.contains("CompressedClassSpaceBaseAddress=" + thisBaseString + " given, but reserving class space failed.")) {
146 // try next one
147 } else if (output.contains("Successfully forced class space address to " + thisBaseString)) {
148 break;
149 } else {
150 throw new RuntimeException("Unexpected");
151 }
152 }
153 if (forceBase >= end) {
154 throw new SkippedException("Failed to force ccs to any of the given bases. Skipping test.");
155 }
156 }
157
158 // Parse the encoding base from the output. In case of CDS, it depends on ASLR. Even in case of CDS=off, we want
159 // to double-check it is the force address.
160 String nKlassBaseString = output.firstMatch("Narrow klass base: 0x([0-9a-f]+)", 1);
161 if (nKlassBaseString == null) {
162 throw new RuntimeException("did not find Narrow klass base in log output");
163 }
164 long nKlassBase = Long.valueOf(nKlassBaseString, 16);
165
166 if (!CDS && nKlassBase != forceBase) {
167 throw new RuntimeException("Weird - we should have mapped at force base"); // .. otherwise we would have skipped out above
168 }
169 if (nKlassBase == 0) {
170 throw new RuntimeException("We should not be running zero-based at this point.");
171 }
172
173 // Calculate the expected crash address pattern. The precise crash address is unknown, but should be located
174 // in the lower part of the guard page following the encoding base. We just accept any address matching the
175 // upper 52 digits (leaving 4K = 12 bits = 4 nibbles of wiggle room)
176 String expectedCrashAddressString = nKlassBaseString.substring(0, nKlassBaseString.length() - 3);
177
178 // output from whitebox function: Klass* should point to encoding base
179 output.shouldMatch("WB_DecodeNKlassAndAccessKlass: nk 0 k 0x" + nKlassBaseString);
180
181 // Then, we should have crashed
182 output.shouldNotHaveExitValue(0);
183 output.shouldContain("# A fatal error has been detected");
184
185 // The hs-err file should contain a reference to the nKlass protection zone, like this:
186 // "RDI=0x0000000800000000 points into nKlass protection zone"
187 File hsErrFile = HsErrFileUtils.openHsErrFileFromOutput(output);
188
189 ArrayList<Pattern> hsErrPatternList = new ArrayList<>();
190 hsErrPatternList.add(Pattern.compile(".*(SIGBUS|SIGSEGV|EXCEPTION_ACCESS_VIOLATION).*"));
191
192 hsErrPatternList.add(Pattern.compile(".*siginfo:.*" + expectedCrashAddressString + ".*"));
193 hsErrPatternList.add(Pattern.compile(".*" + expectedCrashAddressString + ".*points into nKlass protection zone.*"));
194 Pattern[] hsErrPattern = hsErrPatternList.toArray(new Pattern[0]);
195 HsErrFileUtils.checkHsErrFileContent(hsErrFile, hsErrPattern, true);
196 }
197
198 enum Argument { runwb, no_coh_no_cds, no_coh_cds, coh_no_cds, coh_cds };
199 public static void main(String[] args) throws Exception {
200 if (args.length != 1) {
201 throw new RuntimeException("Expecting one argument");
202 }
203 Argument arg = Argument.valueOf(args[0]);
204 System.out.println(arg);
205 switch (arg) {
206 case runwb -> WhiteBox.getWhiteBox().decodeNKlassAndAccessKlass(0);
207 case no_coh_no_cds -> run_test(false, false);
208 case no_coh_cds -> run_test(false, true);
209 // TODO 8348568 Re-enable
210 // case coh_no_cds -> run_test(true, false);
211 // case coh_cds -> run_test(true, true);
212 }
213 }
214 }