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https://issues.apache.org/jira/browse/HDFS-17876?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18053730#comment-18053730
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ASF GitHub Bot commented on HDFS-17876:
---------------------------------------
teamconfx opened a new pull request, #8200:
URL: https://github.com/apache/hadoop/pull/8200
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### Description of PR
This PR fix [HDFS-17876](https://issues.apache.org/jira/browse/HDFS-17876)
### Summary of the change:
- File:
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NameNode.java:1260
- Issue: tracer.close() was called without a null check, inconsistent with
all other resources in the stop() method
- Fix: Added a defensive null check: if (tracer != null) { tracer.close();
}
This prevents a NullPointerException during shutdown if:
1. An exception occurs in the parent constructor before tracer is
initialized
2. The stopAtException() method calls stop() early during initialization
failures
3. Any future refactoring introduces paths where tracer isn't set before
stop() is called
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- [ ] Object storage: have the integration tests been executed and the
endpoint declared according to the connector-specific documentation?
- [ ] If adding new dependencies to the code, are these dependencies
licensed in a way that is compatible for inclusion under [ASF
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> NameNode.stop() missing null check for tracer.close() can cause NPE during
> shutdown
> -----------------------------------------------------------------------------------
>
> Key: HDFS-17876
> URL: https://issues.apache.org/jira/browse/HDFS-17876
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: namenode
> Affects Versions: 3.3.5, 3.3.6
> Reporter: rstest
> Priority: Major
>
> The NameNode.stop() method acks a null check for the tracer field before
> calling tracer.close().
> This is inconsistent with how all other resources are handled in the same
> method and can lead to a NPE during shutdown if the NameNode is stopped
> before fully initializing.
>
> {code:java}
> public void stop() {
> synchronized(this) {
> if (stopRequested)
> return;
> stopRequested = true;
> }
> try {
> if (state != null) { // NULL CHECK
> state.exitState(haContext);
> }
> } catch (ServiceFailedException e) {
> LOG.warn("Encountered exception while exiting state", e);
> } finally {
> stopMetricsLogger();
> stopCommonServices();
> if (metrics != null) { // NULL CHECK
> metrics.shutdown();
> }
> if (namesystem != null) { // NULL CHECK
> namesystem.shutdown();
> }
> if (nameNodeStatusBeanName != null) { // NULL CHECK
> MBeans.unregister(nameNodeStatusBeanName);
> nameNodeStatusBeanName = null;
> }
> if (levelDBAliasMapServer != null) { // NULL CHECK
> levelDBAliasMapServer.close();
> }
> }
> tracer.close(); // NO NULL CHECK
> } {code}
> h2. How tracer Can Be Null
> 1. Exception in parent constructor: If super(conf) at line 1007 throws
> before tracer is initialized at line 1008, tracer remains null.
>
> 2. Early shutdown during initialization: The stopAtException() method (line
> 1048) calls this.stop() when exceptions occur during initialization. If
> initialization fails early, tracer may not be set.
> 3. Subclass or future refactoring: A subclass could override initialization
> behavior or future code changes could introduce paths where tracer isn't
> initialized before stop() is called.
> {code:java}
> java.lang.NullPointerException
> at
> org.apache.hadoop.hdfs.server.namenode.NameNode.stop(NameNode.java:1116)
> at
> org.apache.hadoop.hdfs.server.namenode.NameNode.stopAtException(NameNode.java:1050)
> at
> org.apache.hadoop.hdfs.server.namenode.NameNode.(NameNode.java:1036){code}
> h2. Proposed Fix
> Add a null check for tracer consistent with the other resources in the
> method:
> {code:java}
> if (tracer != null) {
> tracer.close();
> } {code}
>
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