[12] RFR(xs): 8215947: JVM crash with -XX:+DumpSharedSpaces

[Calvin Cheung]

Hi Jiangli,

Thanks for your review and investigation.

There already exists an RFE which was filed by you:
     https://bugs.openjdk.java.net/browse/JDK-8200451
I've linked this bug to the RFE.

thanks,
Calvin

On 1/3/19, 11:40 AM, Jiangli Zhou wrote:
> Hi Calvin,
>
> This looks ok as a short-term fix. We should also investigate the 
> issue at dump time when -XX:-UseCompiler is not specified. The 
> 'assert(_dep_context == DependencyContext::EMPTY...' was done before 
> we changed to allow java code execution at dump time. I just did a 
> quick test to remove the assert and also set _dep_context to 
> DependencyContext::EMPTY in InstanceKlass::remove_unshareable_info(). 
> That allowed dumping to finish without any failure (with  
> -XX:+DumpSharedSpaces and no -XX:-UseCompiler). Could you please file 
> a follow up RFE?
>
> Thanks,
>
> Jiangli
>
>
> On 1/3/19 10:13 AM, Calvin Cheung wrote:
>> bug: https://bugs.openjdk.java.net/browse/JDK-8215947
>>
>> webrev: http://cr.openjdk.java.net/~ccheung/8215947/webrev.00/
>>
>> The bug was filed as confidential, the crash is as follows:
>>
>> $ java -XX:+DumpSharedSpaces
>> narrow_klass_base = 0x0000000800000000, narrow_klass_shift = 3
>> Allocated temporary class space: 1073741824 bytes at 0x00000008c0000000
>> Allocated shared space: 3221225472 bytes at 0x0000000800000000
>> Loading classes to share ...
>> Loading classes to share: done.
>> Rewriting and linking classes ...
>> Rewriting and linking classes: done
>> Number of classes 1229
>>     instance classes = 1168
>>     obj array classes = 53
>>     type array classes = 8
>> Updating ConstMethods ... done.
>> Removing unshareable information ... #
>> # A fatal error has been detected by the Java Runtime Environment:
>> #
>> # Internal Error (instanceKlass.cpp:2288), pid=28024, tid=28031
>> # guarantee(_dep_context == DependencyContext::EMPTY) failed: must be
>> #
>> # JRE version: Java(TM) SE Runtime Environment (11.0.2+7) (build
>> 11.0.2+7-LTS)
>> # Java VM: Java HotSpot(TM) 64-Bit Server VM (11.0.2+7-LTS, mixed mode,
>> tiered, compressed oops, g1 gc, linux-amd64)
>>
>> We currently disable JIT compilation in arguments.cpp if the user 
>> specifies -Xshare:dump.
>>     } else if (match_option(option, "-Xshare:dump")) {
>>       if (FLAG_SET_CMDLINE(bool, DumpSharedSpaces, true) != 
>> JVMFlag::SUCCESS) {
>>         return JNI_EINVAL;
>>       }
>>       set_mode_flags(_int); // Prevent compilation, which creates 
>> objects
>>
>> The proper way to create a shared archive is by specifying 
>> -Xshare:dump instead of -XX:+DumpSharedSpaces.
>> This fix is to disable compilation if DumpSharedSpaces is specified 
>> in Arguments::finalize_vm_init_args().
>>
>> Testing: ran mach5 hs-tier{1,2,3} tests.
>>
>> thanks,
>> Calvin
>