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https://issues.apache.org/jira/browse/HDFS-14321?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16778763#comment-16778763
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Sahil Takiar edited comment on HDFS-14321 at 3/1/19 10:04 PM:
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When running the existing tests with {{\-Xcheck:jni}} I only see one error:
{{FATAL ERROR in native method: Invalid global JNI handle passed to
DeleteGlobalRef}}, which seems to be caused by {{hadoopRzOptionsFree}} calling
{{DeleteGlobalRef}} on {{opts->byteBufferPool}} which is not a global ref. It's
not clear to me how big an issue this is, since {{opts->byteBufferPool}} should
be a local ref that is automatically deleted when the native method exits.
There are a bunch of warnings of the form {{WARNING in native method: JNI call
made without checking exceptions when required to from ...}} - after debugging
these warnings, most of them seem to be caused by the JVM itself (e.g. internal
JDK code). So they would have to fixed within the JDK itself.
was (Author: stakiar):
When running the existing tests with {{-Xcheck:jni}} I only see one error:
{{FATAL ERROR in native method: Invalid global JNI handle passed to
DeleteGlobalRef}}, which seems to be caused by {{hadoopRzOptionsFree}} calling
{{DeleteGlobalRef}} on {{opts->byteBufferPool}} which is not a global ref. It's
not clear to me how big an issue this is, since {{opts->byteBufferPool}} should
be a local ref that is automatically deleted when the native method exits.
There are a bunch of warnings of the form {{WARNING in native method: JNI call
made without checking exceptions when required to from ...}} - after debugging
these warnings, most of them seem to be caused by the JVM itself (e.g. internal
JDK code). So they would have to fixed within the JDK itself.
> Fix -Xcheck:jni issues in libhdfs, run ctest with -Xcheck:jni enabled
> ---------------------------------------------------------------------
>
> Key: HDFS-14321
> URL: https://issues.apache.org/jira/browse/HDFS-14321
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs-client, libhdfs, native
> Reporter: Sahil Takiar
> Assignee: Sahil Takiar
> Priority: Major
>
> The JVM exposes an option called {{-Xcheck:jni}} which runs various checks
> against JNI usage by applications. Further explanation of this JVM option can
> be found in:
> [https://docs.oracle.com/javase/8/docs/technotes/guides/troubleshoot/clopts002.html]
> and
> [https://www.ibm.com/support/knowledgecenter/en/SSYKE2_8.0.0/com.ibm.java.vm.80.doc/docs/jni_debug.html].
> When run with this option, the JVM will print out any warnings or errors it
> encounters with the JNI.
> We should run the libhdfs tests with {{-Xcheck:jni}} (can be added to
> {{LIBHDFS_OPTS}}) and fix any warnings / errors. We should add this option to
> our ctest runs as well to ensure no regressions are introduced to libhdfs.
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