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  1. PDFBox
  2. PDFBOX-3698

Static Initialization Deadlock between COSNumber/COSInteger

    Details

    • Type: Bug
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 2.0.3
    • Fix Version/s: 2.0.5, 3.0.0 PDFBox
    • Component/s: None
    • Labels:
      None
    • Environment:
      Mac OSX 10.12.3, Java(TM) SE Runtime Environment (build 1.8.0_25-b17) Java HotSpot(TM) 64-Bit Server VM (build 25.25-b02, mixed mode)

      Description

      Problem

      Using Tika 1.10 (PDF Box 1.8.10) to parse PDF documents in a multi-threaded application, processing unexpectedly halted. Investigating the output of a kill -3, we found:

      "pool-2-thread-18" #50 prio=5 os_prio=0 tid=0x00002af088a67000 nid=0xc9b9 in Object.wait() [0x00002af0dc803000]
         java.lang.Thread.State: RUNNABLE
        at org.apache.pdfbox.pdfparser.BaseParser.parseDirObject(BaseParser.java:1348)
      
      x 15
      
      "pool-2-thread-13" #45 prio=5 os_prio=0 tid=0x00002af0cf910800 nid=0xc9b4 in Object.wait() [0x00002af0dc2ff000]
         java.lang.Thread.State: RUNNABLE
        at org.apache.pdfbox.cos.COSDocument.getObjectFromPool(COSDocument.java:720)
        at org.apache.pdfbox.pdfparser.PDFParser.parseObject(PDFParser.java:685)
      
      x 2
      
      "pool-2-thread-11" #43 prio=5 os_prio=0 tid=0x00002af0cfba6000 nid=0xc9b2 in Object.wait() [0x00002af0dc0fc000]
         java.lang.Thread.State: RUNNABLE
        at org.apache.pdfbox.cos.COSNumber.<clinit>(COSNumber.java:33)
        at org.apache.pdfbox.pdfparser.BaseParser.parseDirObject(BaseParser.java:1348)
      
      x 1
      

      Upon further investigation, it appears that there is a risk for deadlock when BaseParser calls COSNumber.get() and COSDocument call COSInteger.get().

      I was able to semi-reliably replicate this issue with the below Spock test:

      import org.apache.pdfbox.cos.COSInteger
      import org.apache.pdfbox.cos.COSNumber
      import spock.lang.Specification
      
      class ThreadingIssueSpec extends Specification{
      
          def "testy test"(){
              setup:
              Thread thread = new Thread(new Runnable(){
      
                  @Override
                  void run() {
                      for (int i =0; i<100; i++){
                          COSNumber.get("-")
                      }
                  }
              })
              thread.start()
      
              for(int i =0; i<100; i++) {
                  COSInteger.get("-")
              }
      
              thread.join()
      
              expect:
              1==1
          }
      }
      

      (you'll likely need to run this several times before the test hangs, but it does eventually hang)

      I updated my Tika dep to 1.14 (PDF Box 2.0.3) and was still able to replicate this issue.

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              • Assignee:
                tilman Tilman Hausherr
                Reporter:
                seanstory Sean Story
              • Votes:
                1 Vote for this issue
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                7 Start watching this issue

                Dates

                • Created:
                  Updated:
                  Resolved: