[jira] [Created] (PDFBOX-3698) Static Initialization Deadlock between COSNumber/COSInteger

["Sean Story (JIRA)" <ji...@apache.org>]

Sean Story created PDFBOX-3698:
----------------------------------

             Summary: Static Initialization Deadlock between COSNumber/COSInteger
                 Key: PDFBOX-3698
                 URL: https://issues.apache.org/jira/browse/PDFBOX-3698
             Project: PDFBox
          Issue Type: Bug
    Affects Versions: 2.0.3
         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)
            Reporter: Sean Story


h3. 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:

{noformat}
"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
{noformat}

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:

{noformat}
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
    }
}
{noformat}
(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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