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https://issues.apache.org/jira/browse/HDFS-11436?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16410459#comment-16410459
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Hudson commented on HDFS-11436:
-------------------------------
SUCCESS: Integrated in Jenkins build Hadoop-trunk-Commit #13869 (See
[https://builds.apache.org/job/Hadoop-trunk-Commit/13869/])
HDFS-11436: libhdfs++: Fix race condition in ScopedResolver. (james.clampffer:
rev 606d20c6c0678be0cc7d0163defceacd1ffe03ae)
* (edit)
hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfspp/lib/common/namenode_info.cc
> libhdfs++: Fix race condition in ScopedResolver
> -----------------------------------------------
>
> Key: HDFS-11436
> URL: https://issues.apache.org/jira/browse/HDFS-11436
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: hdfs-client
> Reporter: James Clampffer
> Assignee: James Clampffer
> Priority: Major
> Attachments: HDFS-11436.HDFS-8707.000.patch
>
>
> ScopedResolver holds a shared_ptr to a std::promise to do async stuff while
> the calling thread blocks. The spec allows promise::set_value to unblock
> future::wait immediately which causes future::get_value to race to read
> whatever the promise contains before the state and value owned by the promise
> is destroyed. In this case even though the ScopedResolver holds a shared_ptr
> to the promise which looks like it'd prevent this but it's possible for wait
> to unblock fast enough for the destructor on ScopedResolver to be called
> which ends up destroying the promise. GCC's implementation of promises and
> futures will hit this and will show up in valgrind as a bunch of invalid
> reads if the timings are right to set up the race.
> Simple fix right now is make sure the callback captures a shared_ptr to the
> promise. Longer term fix may be to make a class that encapsulates the
> promise and future with a reference counting mechanism to prevent more of
> these bugs and use that instead of the std lib versions.
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