RFR(S) 8140665: SIGSEGV when a primitive type's class is used as the host class in a call to DefineAnonymousClass call

[Coleen Phillimore]

Hi Harold, This looks good but a single line comment that primitive 
types have NULL Klass* fields in their java.lang.Class instances would 
be helpful, especially if this is changed in the future.

Since the hostClass is checked in the caller, my vote is to not add 
another check in the vm.

In the test, is there going to be another way to get to Unsafe in the 
future, or present?

Thanks,
Coleen


On 3/22/16 11:19 AM, harold seigel wrote:
> Hi Karen,
>
> Thanks for looking at the changes.  The JDK caller of 
> Unsafe_DefineAnonymousClass_impl() is in 
> java.base/share/classes/jdk/internal/misc/Unsafe.java.  It checks for 
> NULL args and throws NPE:
>
>     public Class<?> defineAnonymousClass(Class<?> hostClass, byte[] 
> data, Object[] cpPatches) {
>         if (hostClass == null || data == null) {
>             throw new NullPointerException();
>         }
>         return defineAnonymousClass0(hostClass, data, cpPatches);
>     }
>
> If somehow a null host_class was passed to 
> Unsafe_DefineAnonymousClass_impl() then it would probably seg fault in 
> product.  Perhaps that's okay because it is an Unsafe_... API.
>
> Thanks, Harold
>
> On 3/22/2016 10:57 AM, Karen Kinnear wrote:
>> Harold,
>>
>> Thank you for fixing this. Looks good.
>>
>> One question -
>>
>> 1. If you were to pass in a null host_class in product - what happens?
>> The way I read the resolve_non_null, it asserts in debug that you did 
>> not pass in a null, which suggests to me that it assumes
>> we have already made that check. I would expect and if (host_class == 
>> NULL) || … 0> IllegalArgumentException ?
>>
>> thanks,
>> Karen
>>
>>> On Mar 22, 2016, at 10:23 AM, harold seigel 
>>> <harold.seigel at oracle.com> wrote:
>>>
>>> Hi,
>>>
>>> Please review this small change to fix bug 8140665.
>>>
>>> Instead of asserting or getting a SIGSEGV when trying to define an 
>>> anonymous class when the host class is a primitive type, this fix 
>>> throws an IllegalArgumentException.
>>>
>>> Webrev: http://cr.openjdk.java.net/~hseigel/bug_8140665/
>>>
>>> JBS Bug: https://bugs.openjdk.java.net/browse/JDK-8140665
>>>
>>> The fix was tested with JCK Lang and VM java_lang tests, the UTE 
>>> non-collated quick tests, and the hotspot, JDK vm, java/io, 
>>> java/lang, java/util and JFR JTreg tests, and the test included in 
>>> this RFR.
>>>
>>> Thanks, Harold
>