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https://issues.apache.org/jira/browse/PYLUCENE-17?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13400965#comment-13400965
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Patrick J. McNerthney commented on PYLUCENE-17:
-----------------------------------------------
What I mean by "class static fields" are those fields of the Java class that
are declared as static. java.lang.Boolean is a good example, with it's TRUE
and FALSE static fields. If you look at the Boolean::initializeClass generated
code, it looks like this:
jclass Boolean::initializeClass(bool getOnly)
{
if (getOnly)
return (jclass) (class$ == NULL ? NULL : class$->this$);
if (!class$)
{
jclass cls = (jclass) env->findClass("java/lang/Boolean");
mids$ = new jmethodID[max_mid];
mids$[mid_init$_bb0c767f] = env->getMethodID(cls, "<init>", "(Z)V");
mids$[mid_init$_5fdc3f48] = env->getMethodID(cls, "<init>",
"(Ljava/lang/String;)V");
mids$[mid_booleanValue_54c6a16a] = env->getMethodID(cls,
"booleanValue", "()Z");
mids$[mid_compareTo_d07f0c91] = env->getMethodID(cls, "compareTo",
"(Ljava/lang/Boolean;)I");
mids$[mid_compareTo_290588f1] = env->getMethodID(cls, "compareTo",
"(Ljava/lang/Object;)I");
mids$[mid_equals_290588e2] = env->getMethodID(cls, "equals",
"(Ljava/lang/Object;)Z");
mids$[mid_getBoolean_5fdc3f44] = env->getStaticMethodID(cls,
"getBoolean", "(Ljava/lang/String;)Z");
mids$[mid_hashCode_54c6a179] = env->getMethodID(cls, "hashCode", "()I");
mids$[mid_parseBoolean_5fdc3f44] = env->getStaticMethodID(cls,
"parseBoolean", "(Ljava/lang/String;)Z");
mids$[mid_toString_14c7b5c5] = env->getMethodID(cls, "toString",
"()Ljava/lang/String;");
mids$[mid_toString_445a175e] = env->getStaticMethodID(cls, "toString",
"(Z)Ljava/lang/String;");
mids$[mid_valueOf_a98d5bba] = env->getStaticMethodID(cls, "valueOf",
"(Z)Ljava/lang/Boolean;");
mids$[mid_valueOf_9d4a8ff9] = env->getStaticMethodID(cls, "valueOf",
"(Ljava/lang/String;)Ljava/lang/Boolean;");
class$ = (::java::lang::Class *) new JObject(cls);
FALSE = new Boolean(env->getStaticObjectField(cls, "FALSE",
"Ljava/lang/Boolean;"));
TRUE = new Boolean(env->getStaticObjectField(cls, "TRUE",
"Ljava/lang/Boolean;"));
TYPE = new ::java::lang::Class(env->getStaticObjectField(cls, "TYPE",
"Ljava/lang/Class;"));
}
return (jclass) class$->this$;
}
In the code above the class$ variable is set to a non NULL value before the
FALSE, TRUE, and TYPE class static fields are in fact properly initialized. So
calling Boolean::initializeClass does not 100% ensure that those static fields
are for sure, *for* *sure*, correctly initialized.
> 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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