Race condition in JedisSentinelPool.initPool() causes JedisConnectionException on getResource()

[mp911de]

JedisSentinelPool.initPool() is called concurrently by multiple threads during statup: The thread creating JedisSentinelPool and MasterListener. The consequence is that calls to getResource() fail with an exception.

Reproduction of the issue requires just the right timing so calling the offending code in a while(true) loop allows reproduction instead of single-shot execution.

Jedis version: 3.0.0

redis.clients.jedis.exceptions.JedisConnectionException: Could not get a resource from the pool

	at redis.clients.jedis.util.Pool.getResource(Pool.java:59)
	at redis.clients.jedis.JedisSentinelPool.getResource(JedisSentinelPool.java:209)
	at org.springframework.data.redis.connection.jedis.Reproducer.reproduceSentinelPoolRaceCondition(Reproducer.java:43)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
	at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
	at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
	at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
Caused by: java.lang.NullPointerException
	at redis.clients.jedis.util.Pool.getResource(Pool.java:50)
	... 24 more

Reproducer

public class Reproducer {

  @Test
  public void reproduceSentinelPoolRaceCondition() {

    while (true) {

      GenericObjectPoolConfig poolConfig = new JedisPoolConfig();
      JedisSentinelPool jedisSentinelPool = new JedisSentinelPool("mymaster",
          new HashSet<>(Arrays.asList("127.0.0.1:26379", "127.0.0.1:26380")), 
          poolConfig, 1000, 1000, null, 0,
          "jedis-client");

      jedisSentinelPool.getResource().close();

      jedisSentinelPool.destroy();
    }
  }
}

[gkorland]

It seems like a race condition between the main thread running the Constructor and then initPool() and the sentinel listeners threads are also trying to call initPool() in parallel

[gkorland]

#1566 it seems like this fix is the source of this bug