[jira] [Created] (MAPREDUCE-6527) Data race on field org.apache.hadoop.mapred.JobConf.credentials

["Ali Kheradmand (JIRA)" <ji...@apache.org>]

Ali Kheradmand created MAPREDUCE-6527:
-----------------------------------------

             Summary: Data race on field org.apache.hadoop.mapred.JobConf.credentials
                 Key: MAPREDUCE-6527
                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-6527
             Project: Hadoop Map/Reduce
          Issue Type: Bug
            Reporter: Ali Kheradmand


I am running the test suite against a dynamic race detector called RV-Predict. Here is a race report that I got: 

Data race on field org.apache.hadoop.mapred.JobConf.credentials: {{{
    Concurrent read in thread T327 (locks held: {})
 ---->  at org.apache.hadoop.mapred.JobConf.getCredentials(JobConf.java:505)
        at org.apache.hadoop.mapreduce.task.JobContextImpl.<init>(JobContextImpl.java:70)
        at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:524)
    T327 is created by T22
        at org.apache.hadoop.mapred.LocalJobRunner$Job.<init>(LocalJobRunner.java:218)

    Concurrent write in thread T22 (locks held: {Monitor@496c673a, Monitor@496319b0})
 ---->  at org.apache.hadoop.mapred.JobConf.setCredentials(JobConf.java:510)
        at org.apache.hadoop.mapred.LocalJobRunner.submitJob(LocalJobRunner.java:787)
        at org.apache.hadoop.mapreduce.JobSubmitter.submitJobInternal(JobSubmitter.java:241)
        at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1290)
        at javax.security.auth.Subject.doAs(Subject.java:422)
        at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1669)
        at org.apache.hadoop.mapreduce.Job.submit(Job.java:1287)
        at org.apache.hadoop.mapreduce.lib.jobcontrol.ControlledJob.submit(ControlledJob.java:335)
        - locked Monitor@496319b0 at org.apache.hadoop.mapreduce.lib.jobcontrol.ControlledJob.submit(ControlledJob.java:n/a) 
        at org.apache.hadoop.mapreduce.lib.jobcontrol.JobControl.run(JobControl.java:245)
        - locked Monitor@496c673a at org.apache.hadoop.mapreduce.lib.jobcontrol.JobControl.run(JobControl.java:229) 
    T22 is created by T1
        at org.apache.hadoop.mapred.jobcontrol.TestJobControl.doJobControlTest(TestJobControl.java:111)
}}}

In the source code of org.apache.hadoop.mapreduce.JobStatus.submitJob function, we have the following lines:
    Job job = new Job(JobID.downgrade(jobid), jobSubmitDir);
    job.job.setCredentials(credentials);

It looks a bit suspicious: Job extends thread and at the end of its constructor it starts a new thread which creates a new instance of JobContextImpl which reads credentials. However, the first thread concurrently sets credentials after a creating the Job instance. 





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