RFR (S) 8016075 - Win32 crash with CDS enabled and small heap size

[Christian Thalinger]

On Jun 27, 2013, at 6:42 AM, harold seigel <harold.seigel at oracle.com> wrote:

> Hi Ioi,
> 
> The changes look good. 
> 
> You can simplify MetaspaceShared::is_in_shared_space(...) to something like:
> // Return true if given address is in the mapped shared space.
> bool MetaspaceShared::is_in_shared_space(const void* p) {
>   return UseSharedSpaces && FileMapInfo::current_info()->is_in_shared_space(p);
> }

Would it be possible to change that method to also return a valid answer when dumping shared spaces?  I'd need this for something else I'm working on.

-- Chris
> 
> Thanks, Harold
> 
> On 6/27/2013 12:10 AM, Ioi Lam wrote:
>> Please review a small fix:
>> 
>>     http://cr.openjdk.java.net/~iklam/8016075/cds_is_shared_crash_003/
>> 
>> Bug: Win32 crash with CDS enabled and small heap size
>> 
>>     http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8016075
>>     https://jbs.oracle.com/bugs/browse/JDK-8016075
>> 
>> Summary of fix:
>> 
>>     The function MetaspaceShared::is_in_shared_space() was testing with
>>     incorrect bounds. As a resullt, a dynamically loaded InstanceKlass
>>     was incorrectly identified as an InstanceKlass stored in the CDS
>>     archive. This caused the following code to fail:
>> 
>>     bool InstanceKlass::link_class_impl(...) {
>>       ...
>>       if (!this_oop()->is_shared()) {
>>         ResourceMark rm(THREAD);
>>         this_oop->vtable()->initialize_vtable(true, CHECK_false); //<< failed to execute
>>         this_oop->itable()->initialize_itable(true, CHECK_false);
>>       }
>> 
>>     Hence, Method::vtable_index() could return an incorrect value for some
>>     Methods, leading to various mysterious crashes.
>> 
>>     The fix is for MetaspaceShared::is_in_shared_space() to consider the actual used
>>     spaces in the CDS archive regions.
>> 
>> Tests:
>> 
>>     JPRT
>>     UTE (vm.runtime.testlist, vm.quick.testlist, vm.parallel_class_loading.testlist)
>> 
>> Thanks
>> - Ioi
>> 
>> 
>> 
> 

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