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  1. ZooKeeper
  2. ZOOKEEPER-893

ZooKeeper high cpu usage when invalid requests

    Details

    • Type: Bug
    • Status: Closed
    • Priority: Critical
    • Resolution: Fixed
    • Affects Version/s: 3.3.1
    • Fix Version/s: 3.3.2, 3.4.0
    • Component/s: server
    • Labels:
      None
    • Environment:

      Linux 2.6.16
      4x Intel(R) Xeon(R) CPU X3320 @ 2.50GHz
      java version "1.6.0_17"
      Java(TM) SE Runtime Environment (build 1.6.0_17-b04)
      Java HotSpot(TM) Server VM (build 14.3-b01, mixed mode)

    • Hadoop Flags:
      Reviewed
    • Tags:
      zookeeper server cpu ZOOKEEPER-427

      Description

      When ZooKeeper receives certain illegally formed messages on the internal communication port (:4181 by default), it's possible for ZooKeeper to enter an infinite loop which causes 100% cpu usage. It's related to ZOOKEEPER-427, but that patch does not resolve all issues.

      from: src/java/main/org/apache/zookeeper/server/quorum/QuorumCnxManager.java

      the two affected parts:
      ===========
      int length = msgLength.getInt();
      if(length <= 0) {
      throw new IOException("Invalid packet length:" + length);
      }
      ===========

      ===========
      while (message.hasRemaining()) {
      temp_numbytes = channel.read(message);
      if(temp_numbytes < 0)

      { throw new IOException("Channel eof before end"); }


      numbytes += temp_numbytes;
      }
      ===========

      how to replicate this bug:

      perform an nmap portscan against your zookeeper server: "nmap -sV -n your.ip.here -p4181"
      wait for a while untill you see some messages in the logfile and then you will see 100% cpu usage. It does not recover from this situation. With my patch, it does not occur anymore

        Attachments

        1. ZOOKEEPER-893-3.3.patch
          5 kB
          Flavio Junqueira
        2. ZOOKEEPER-893.patch
          2 kB
          Thijs Terlouw
        3. ZOOKEEPER-893.patch
          5 kB
          Flavio Junqueira

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              • Assignee:
                tt Thijs Terlouw
                Reporter:
                tt Thijs Terlouw
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                • Created:
                  Updated:
                  Resolved:

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