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https://issues.apache.org/jira/browse/HDFS-6254?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13982392#comment-13982392
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Chris Nauroth commented on HDFS-6254:
-------------------------------------
Regarding this line of code:
{code}
fs = hdfsBuilderConnect(bld); //core dump here
{code}
This is attempting to use a {{hdfsBuilder}} that had already been used in an
earlier {{hdfsBuilderConnect}} call. This is invalid usage and could very well
produce a segfault. The docs for {{hdfsBuilderConnect}} state that it always
frees the builder, regardless of the outcome:
{code}
* The HDFS builder will be freed, whether or not the connection was
* successful.
{code}
Related to this, the docs for {{hdfsFreeBuilder}} state that you normally
wouldn't need to call it directly:
{code}
* It is normally not necessary to call this function since
* hdfsBuilderConnect frees the builder.
{code}
The only time you'd need to call {{hdfsFreeBuilder}} yourself directly is if
you allocated one by calling {{hdfsNewBuilder}}, but then never called
{{hdfsBuilderConnect}}. I don't see a path through your code sample that can
cause that to happen, so I expect you can remove the null checks on {{bld}}
followed by the calls to {{hdfsFreeBuilder}}.
If there are any additional libhdfs usage questions, I recommend emailing
u...@hadoop.apache.org. This is the best venue for support. Jira is intended
for reporting of bugs only, and in this case, we haven't seen any actual bugs
in libhdfs.
> hdfsConnect segment fault where namenode not connected
> ------------------------------------------------------
>
> Key: HDFS-6254
> URL: https://issues.apache.org/jira/browse/HDFS-6254
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: libhdfs
> Affects Versions: 2.2.0
> Environment: Linux Centos 64bit
> Reporter: huang ken
> Assignee: Chris Nauroth
> Attachments: test.cpp
>
>
> When namenode is not started, the libhdfs client will cause segment fault
> while connecting.
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