Crash with TraceClassLoading

[Staffan Larsen]

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());
> 
> Jeremy
> <Makefile><tcl.cc>