[HADOOP-15538] Possible RPC deadlock in Client

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: common
• Assignee: Yongjun Zhang
• Reporter: Yongjun Zhang
• Created: 14/Jun/18 06:52
• Updated: 14/Sep/20 15:51

Description

We have a jstack collection that spans 13 minutes. One frame per ~1.5 minutes. And for each of the frame, I observed the following:

Found one Java-level deadlock:
=============================
"IPC Parameter Sending Thread #294":
  waiting to lock monitor 0x00007f68f21f3188 (object 0x0000000621745390, a java.lang.Object),
  which is held by UNKNOWN_owner_addr=0x00007f68332e2800

Java stack information for the threads listed above:
===================================================
"IPC Parameter Sending Thread #294":
        at sun.nio.ch.SocketChannelImpl.ensureWriteOpen(SocketChannelImpl.java:268)
        - waiting to lock <0x0000000621745390> (a java.lang.Object)
        at sun.nio.ch.SocketChannelImpl.write(SocketChannelImpl.java:461)
        - locked <0x0000000621745380> (a java.lang.Object)
        at org.apache.hadoop.net.SocketOutputStream$Writer.performIO(SocketOutputStream.java:63)
        at org.apache.hadoop.net.SocketIOWithTimeout.doIO(SocketIOWithTimeout.java:142)
        at org.apache.hadoop.net.SocketOutputStream.write(SocketOutputStream.java:159)
        at org.apache.hadoop.net.SocketOutputStream.write(SocketOutputStream.java:117)
        at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:82)
        at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:140)
        - locked <0x0000000621749850> (a java.io.BufferedOutputStream)
        at java.io.DataOutputStream.flush(DataOutputStream.java:123)
        at org.apache.hadoop.ipc.Client$Connection$3.run(Client.java:1072)
        - locked <0x000000062174b878> (a java.io.DataOutputStream)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at java.lang.Thread.run(Thread.java:748)

Found one Java-level deadlock:
=============================
"IPC Client (297602875) connection to x.y.z.p:8020 from impala":
  waiting to lock monitor 0x00007f68f21f3188 (object 0x0000000621745390, a java.lang.Object),
  which is held by UNKNOWN_owner_addr=0x00007f68332e2800

Java stack information for the threads listed above:
===================================================
"IPC Client (297602875) connection to x.y.z.p:8020 from impala":
        at sun.nio.ch.SocketChannelImpl.readerCleanup(SocketChannelImpl.java:279)
        - waiting to lock <0x0000000621745390> (a java.lang.Object)
        at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:390)
        - locked <0x0000000621745370> (a java.lang.Object)
        at org.apache.hadoop.net.SocketInputStream$Reader.performIO(SocketInputStream.java:57)
        at org.apache.hadoop.net.SocketIOWithTimeout.doIO(SocketIOWithTimeout.java:142)
        at org.apache.hadoop.net.SocketInputStream.read(SocketInputStream.java:161)
        at org.apache.hadoop.net.SocketInputStream.read(SocketInputStream.java:131)
        at java.io.FilterInputStream.read(FilterInputStream.java:133)
        at java.io.FilterInputStream.read(FilterInputStream.java:133)
        at org.apache.hadoop.ipc.Client$Connection$PingInputStream.read(Client.java:553)
        at java.io.BufferedInputStream.fill(BufferedInputStream.java:246)
        at java.io.BufferedInputStream.read(BufferedInputStream.java:265)
        - locked <0x00000006217476f0> (a java.io.BufferedInputStream)
        at java.io.DataInputStream.readInt(DataInputStream.java:387)
        at org.apache.hadoop.ipc.Client$Connection.receiveRpcResponse(Client.java:1113)
        at org.apache.hadoop.ipc.Client$Connection.run(Client.java:1006)

Found 2 deadlocks.

This happens with jdk1.8.0_162 on 2.6.32-696.18.7.el6.x86_64.

The code appears to match https://github.com/tuxjdk/jdk8u/blob/master/jdk/src/share/classes/sun/nio/ch/SocketChannelImpl.java.

The first thread is blocked at:

https://github.com/tuxjdk/jdk8u/blob/master/jdk/src/share/classes/sun/nio/ch/SocketChannelImpl.java#L268

[The second thread is blocked at:
https://github.com/tuxjdk/jdk8u/blob/master/jdk/src/share/classes/sun/nio/ch/SocketChannelImpl.java#L279

There are two issues here:

1. There seems to be a real deadlock because the stacks remain the same even if the first an last jstack frames captured is 13 minutes apart.
2. Java deadlock report seems to be problematic, two threads that have deadlock should not be blocked on the same lock, but they appear to be in this case: the same SocketChannelImpl's stateLock.

I found a relevant jdk jira https://bugs.openjdk.java.net/browse/JDK-8007476, it explains where two deadlocks are reported and they are really for the same deadlock.

I don't see a similar report about this issue in jdk jira database, and I'm thinking about filing a jdk jira for that, but would like to throw some discussion here before that.

Issue#1 is important, because the client is hanging, which indicate a real problem; however, without a correct report before issue#2 is fixed, it's not clear how the deadlock really looks like.

Thanks.

Issue Links

• is related to: IMPALA-7482 Deadlock with unknown lock holder in JVM in java.security.Provider.getService()
• relates to: HADOOP-15530 RPC could stuck at senderFuture.get()