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https://issues.apache.org/jira/browse/PYLUCENE-17?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13400899#comment-13400899
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Andi Vajda commented on PYLUCENE-17:
------------------------------------
While there could be something like your scenario going on, I'm not sure it's a
problem (I'm a bit confused right now).
The static fields are not initialized during initializeClass() and their
initialization is not triggered by initializeClass() either (your step 1 there
is incomplete). The static fields are setup during <class>::initialize() which
is called by the __initialize__() calls defined in __init__.cpp which are
called by the main __initialize__() function which is what is called when you
call initVM() from Python for your module (thus why it is important to call the
initVM() that comes with your module).
If importing the module and calling initVM() is all done in one thread, the
main one, others not running until initVM is complete, then I don't even
understand right now (I'm confused, I said :-), how we can even get this bug.
But I reproduced it, so I'm not arguing anything, just trying to wrap my head
around this process again.
Right now, I'm clearly missing something. I don't understand why this bug even
happened in the first place anymore :-(
> Possible race condition with pylucene attachCurrentThread
> ---------------------------------------------------------
>
> Key: PYLUCENE-17
> URL: https://issues.apache.org/jira/browse/PYLUCENE-17
> Project: PyLucene
> Issue Type: Bug
> Environment: Linux 2.6.39
> Sun jdk 1.6.26
> Reporter: Greg Bowyer
> Labels: pylucene
> Attachments: PYLUCENE-17-3.patch, PYLUCENE-17-4.patch, backtrace,
> diff.17.txt, lucene-threadtest.py
>
>
> It looks like there is a possible race that can cause null pointer exceptions
> in the JVM, making it crash
> Because its a race it is hard to reproduce, the best luck I have had so far
> is dropping my FS cache in the OS, which seems to slow down the
> initialisation of the JVM enough to make it easier to reproduce.
> Attached is my test case
> Test session follows
> ---------------------------------------------------------------
> greg@localhost ~/programming/python $ sudo bash -c 'echo 3 >
> /proc/sys/vm/drop_caches'
> greg@localhost ~/programming/python $ python ./lucene-threadtest.py
> #
> # A fatal error has been detected by the Java Runtime Environment:
> #
> # SIGSEGV (0xb) at pc=0x00007f79226b35c8, pid=26581, tid=140158003312384
> #
> # JRE version: 6.0_26-b03
> # Java VM: Java HotSpot(TM) 64-Bit Server VM (20.1-b02 mixed mode linux-amd64
> compressed oops)
> # Problematic frame:
> # V [libjvm.so+0x4b05c8] instanceKlass::cached_itable_index(unsigned
> long)+0x18
> #
> # An error report file with more information is saved as:
> # /home/greg/programming/python/hs_err_pid26581.log
> #
> # If you would like to submit a bug report, please visit:
> # http://java.sun.com/webapps/bugreport/crash.jsp
> #
> Aborted (core dumped)
> greg@localhost ~/programming/python $ python ./lucene-threadtest.py
> greg@localhost ~/programming/python $ python ./lucene-threadtest.py
> greg@localhost ~/programming/python $ python ./lucene-threadtest.py
> greg@localhost ~/programming/python $ rm -r /tmp/test-index/
> greg@localhost ~/programming/python $ sudo bash -c 'echo 3 >
> /proc/sys/vm/drop_caches'
> greg@localhost ~/programming/python $ python ./lucene-threadtest.py
> #
> # A fatal error has been detected by the Java Runtime Environment:
> [thread 139988165344768 also had an error][thread 139988165344768 also had an
> error]#
> # SIGSEGV (0xb)
> at pc=0x00007f5197550a29, pid=27657, tid=139988039468800
> #
> # JRE version: 6.0_26-b03
> # Java VM: Java HotSpot(TM) 64-Bit Server VM (20.1-b02 mixed mode linux-amd64
> compressed oops)
> # Problematic frame:
> # V [libjvm.so+0x4f2a29] unsigned+0x299
> #
> # An error report file with more information is saved as:
> # /home/greg/programming/python/hs_err_pid27657.log
> #
> # If you would like to submit a bug report, please visit:
> # http://java.sun.com/webapps/bugreport/crash.jsp
> #
> Aborted (core dumped)
> greg@localhost ~/programming/python $ python ./lucene-threadtest.py
> greg@localhost ~/programming/python $ sudo bash -c 'echo 3 >
> /proc/sys/vm/drop_caches'
> greg@localhost ~/programming/python $ python ./lucene-threadtest.py
> #
> # A fatal error has been detected by the Java Runtime Environment:
> #
> # SIGSEGV (0xb) at pc=0x00007f51bc2eaa1e, pid=28124, tid=139988377052928
> #
> # JRE version: 6.0_26-b03
> # Java VM: Java HotSpot(TM) 64-Bit Server VM (20.1-b02 mixed mode linux-amd64
> compressed oops)
> # Problematic frame:
> # V [libjvm.so+0x4f2a1e] unsigned+0x28e
> #
> # An error report file with more information is saved as:
> # /home/greg/programming/python/hs_err_pid28124.log
> #
> # If you would like to submit a bug report, please visit:
> # http://java.sun.com/webapps/bugreport/crash.jsp
> #
> Aborted (core dumped)
> greg@localhost ~/programming/python $
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