RFR(XS) 8008750 [partfait] Null pointer deference in hotspot/src/share/vm/oops/instanceKlass.hpp

[David Holmes]

If we can _prove_ these can never be null then we should be adding these 
to a whitelist for parfait so that it doesn't report them. We should not 
have to add redundant checks to satisfy noisy tools.

David

On 6/03/2013 10:46 AM, Morris Meyer wrote:
> Thanks for the review Coleen and Vladimir.  Here's the updated webrev.
>
>          --mm
>
> WEBREV - http://cr.openjdk.java.net/~morris/8008750.02
>
> On 3/5/13 6:16 PM, Vladimir Kozlov wrote:
>> On 3/5/13 2:39 PM, Coleen Phillimore wrote:
>>>
>>> Oh, I see.  Can you still use assert rather then ShouldNotReachHere()?
>>> The former will vanish in product but the latter is added in product.
>>
>> Yes, I think we can remove "else { ShouldNotReachHere();" in header
>> file instanceKlass.hpp and add assert. Method set_host_klass() has the
>> assert already, we need to add assert to set_implementor().
>>
>> Also in instanceKlass.cpp, Morris, could you reverse check
>> InstanceKlass::clean_implementors_list()?
>>
>> Thanks,
>> Vladimir
>>
>>>
>>> Coleen
>>>
>>> On 03/05/2013 05:17 PM, Vladimir Kozlov wrote:
>>>> We want to fix cases where Parfait gives "false" positives. That is
>>>> why we need real != NULL check, assert does not help.
>>>>
>>>> Vladimir
>>>>
>>>> On 3/5/13 1:50 PM, Coleen Phillimore wrote:
>>>>> I can't see the parfait link in the bug.
>>>>>
>>>>> What does this change do but check for null in the cases where host
>>>>> class and adr_implementers can't be null?
>>>>>
>>>>> In instanceKlass.hpp ShouldNotReachHere() is enabled in product so
>>>>> these
>>>>> should be
>>>>> assert(host != NULL, "not null");
>>>>> *adr = host;
>>>>>
>>>>> I don't understand the motivation for this change and would rather not
>>>>> enable these ShouldNotReachHere() in product mode, ie use asserts
>>>>> instead.
>>>>>
>>>>> Coleen
>>>>>
>>>>> On 03/05/2013 03:51 PM, Vladimir Kozlov wrote:
>>>>>> Looks good. CC to runtime group.
>>>>>>
>>>>>> Vladimir
>>>>>>
>>>>>> On 3/5/13 12:37 PM, Morris Meyer wrote:
>>>>>>> Folks,
>>>>>>>
>>>>>>> Could I get a review for this parfait issue? This has been through
>>>>>>> JPRT.
>>>>>>>
>>>>>>> Thanks much,
>>>>>>>
>>>>>>>          --mm
>>>>>>>
>>>>>>> WEBREV - http://cr.openjdk.java.net/~morris/8008750.01
>>>>>>> BUG - https://jbs.oracle.com/bugs/browse/JDK-8008750
>>>>>
>>>
>