Crash with TraceClassLoading

[Staffan Larsen]

On 8 jan 2014, at 06:11, David Holmes <david.holmes at oracle.com> wrote:

> On 7/01/2014 9:46 PM, Staffan Larsen wrote:
>> This looks good to me. I can sponsor the fix once we have second review.
>> 
>> It’s unfortunate that our current test infrastructure does not allow us to write tests with native code…
>> 
>> /Staffan
>> 
>> 
>> On 19 dec 2013, at 21:01, Jeremy Manson <jeremymanson at google.com> wrote:
>> 
>>> Now that 9 is underway, presumably we can start feeding back fixes again.
>>> 
>>> This one's a bit obscure.  TraceClassLoading expects there to be a (Java) caller when you load a class with the bootstrap class loader.  However, there are ways of loading a class that don't involve having a Java caller.  For example, you can do so from a JVMTI hook.  A reproduction is attached, and here's a patch:
>>> 
>>> diff --git a/src/share/vm/classfile/classFileParser.cpp b/src/share/vm/classfile/classFileParser.cpp
>>> --- a/src/share/vm/classfile/classFileParser.cpp
>>> +++ b/src/share/vm/classfile/classFileParser.cpp
>>> @@ -4098,8 +4098,12 @@
>>>         tty->print("[Loaded %s from %s]\n", this_klass->external_name(),
>>>                    cfs->source());
>>>       } else if (class_loader.is_null()) {
>>> -        if (THREAD->is_Java_thread()) {
>>> -          Klass* caller = ((JavaThread*)THREAD)->security_get_caller_class(1);
>>> +        Klass* caller =
>>> +            THREAD->is_Java_thread()
>>> +                ? ((JavaThread*)THREAD)->security_get_caller_class(1)
>>> +                : NULL;
>>> +        // caller can be NULL, for example, during a JVMTI VM_Init hook
>>> +        if (caller != NULL) {
>>>           tty->print("[Loaded %s by instance of %s]\n",
>>>                      this_klass->external_name(),
>>>                      InstanceKlass::cast(caller)->external_name());
> 
> Shouldn't we have an "else" there to say "loaded %s via native mechanism" or something like that?

I think the next line (not shown in the diff above) is the “else” you are looking for.

/Staffan

> 
> Thanks,
> David
> 
> 
>>> Jeremy
>>> <Makefile><tcl.cc>

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