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Re: [PATCH] Fix for a JNI bug in CreateJ.cpp (JavaHL)

From: Hyrum K. Wright <hyrum_wright_at_mail.utexas.edu>
Date: Tue, 18 May 2010 22:25:22 -0500

On Tue, May 18, 2010 at 10:14 PM, Byeongcheol Lee <lineonking_at_gmail.com>wrote:

> Dear Subversion Developers:
>
> I attach a patch for a JNI bug. To reproduce the bug, run your JavaHL
> regression test under our dynamic JNI bug detector, Jinn
> [http://userweb.cs.utexas.edu/~bclee/jinn<http://userweb.cs.utexas.edu/%7Ebclee/jinn>
> ].
>
> $env JAVA_TOOL_OPTIONS=-agentlib:jinn make check-javahl
> ...
> .Exception in thread "main" xtc.lang.blink.agent.JNIAssertionFailure:
> The return type mismatch in CallObjectMethodV: method 0x9626fe4 has
> return type: (Ljava/lang/Object;)Z
> at
> xtc.lang.blink.agent.JNIAssertionFailure.assertFail(JNIAssertionFailure.java:16)
> at org.apache.subversion.javahl.SVNClient.doImport(Native Method)
> at org.apache.subversion.javahl.SVNTests.setUp(SVNTests.java:239)
> at junit.framework.TestCase.runBare(TestCase.java:128)
> at junit.framework.TestResult$1.protect(TestResult.java:106)
> at junit.framework.TestResult.runProtected(TestResult.java:124)
> at junit.framework.TestResult.run(TestResult.java:109)
> at junit.framework.TestCase.run(TestCase.java:120)
> at junit.framework.TestSuite.runTest(TestSuite.java:230)
> at junit.framework.TestSuite.run(TestSuite.java:225)
> at junit.framework.TestSuite.runTest(TestSuite.java:230)
> at junit.framework.TestSuite.run(TestSuite.java:225)
> at junit.textui.TestRunner.doRun(TestRunner.java:121)
> at junit.textui.TestRunner.doRun(TestRunner.java:114)
> at junit.textui.TestRunner.run(TestRunner.java:77)
> at org.apache.subversion.javahl.RunTests.main(RunTests.java:116)
> ...
>
> To understand what caused the JNI error, I attached a gdb to the JVM.
> Relevant caling context and source lines are here.
>
> #5 0x8f86cdf5 in CreateJ::Set (objects=...)
> at subversion/bindings/javahl/native/CreateJ.cpp:912
> #6 0x8f86bf4f in CommitMessage::getCommitMessage (this=0x81bf6d0,
> commit_items=0x817ea60)
> at subversion/bindings/javahl/native/CommitMessage.cpp:210
> ...
> #11 0x8f88bff0 in Java_org_apache_subversion_javahl_SVNClient_doImport (
> env=0x805a518, jthis=0xb7281ce4, jpath=0xb7281ce0, jurl=0xb7281cdc,
> jmessage=0x0, jdepth=0xb7281cd4, jnoIgnore=0 '\000',
> jignoreUnknownNodeTypes=0 '\000', jrevpropTable=0x0)
> at
> subversion/bindings/javahl/native/org_apache_subversion_javahl_SVNClient.cpp:792
>
> In subversion/bindings/javahl/native/CreateJ.cpp
> ...
> 883 jclass clazz = env->FindClass("java/util/HashSet");
> ...
> 895 static jmethodID add_mid = 0;
> ...
> 898 add_mid = env->GetMethodID(clazz, "add",
> "(Ljava/lang/Object;)Z");
> ...
> 912 env->CallObjectMethod(set, add_mid, jthing);
> ...
>
>
> There is a JNI type mismatch between Line 898 and 912.
> The "add_mid" at Line 898 points a Java method returning a boolean
> value, but the
> JNI function at Line 912 assumes that "add_mid" is returning a Java
> reference.
> This violates a JNI programming rule:
>
> "You should replace type in Call<type>Method with the Java type of the
> method you are calling"
> [
> http://java.sun.com/javase/6/docs/technotes/guides/jni/spec/functions.html#wp4256
> ]
>
> The fix is trivial and obvious, and line 912 must change its JNI
> function from "CallObjectMethod"
> to "CallBooleanMethod."
>

The patch looks sound. Would you write a log message, per the patch
submission guidelines[1]? You can find our log message format at [2].

Thanks!

-Hyrum

[1] http://subversion.apache.org/docs/community-guide/general.html#patches
[2]
http://subversion.apache.org/docs/community-guide/conventions.html#log-messages
Received on 2010-05-19 05:25:57 CEST

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