(S) RFR: 8154589: assert(k != NULL) failed: preloaded klass not initialized

[serguei.spitsyn at oracle.com]

David,

It looks good.

Thanks,
Serguei


On 5/24/16 22:05, David Holmes wrote:
> Bug: https://bugs.openjdk.java.net/browse/JDK-8154589
>
> webrev: http://cr.openjdk.java.net/~dholmes/8154589/webrev/
>
> We sometimes see tests failing with a VM assertion failure that a 
> klass was not loaded (the actual assertion message is wrong):
>
> # assert(k != NULL) failed: preloaded klass not initialized
>
> Stack: [0xfffffd7fa80ff000,0xfffffd7fa81ff000], sp=0xfffffd7fa81fc570, 
> free space=1013k
> Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, 
> C=native code)
> V [libjvm.so+0x2a01a57] void VMError::report(outputStream*)+0x937
> V [libjvm.so+0x2a02e4b] void VMError::report_and_die()+0x55f
> V [libjvm.so+0x10b670b] void report_vm_error(const char*,int,const 
> char*,const char*)+0x55f
> V [libjvm.so+0x28937e5] void 
> ConcurrentLocksDump::dump_at_safepoint()+0x43d
> V [libjvm.so+0x287ab7e] void 
> Threads::print_on(outputStream*,bool,bool,bool)+0xcce
> V [libjvm.so+0x2a372a7] void VM_PrintThreads::doit()+0x1b
> V [libjvm.so+0x2a366e9] void VM_Operation::evaluate()+0xc5
>
>
> In a few of the VMOperation doit_prologue methods we have this logic 
> to ensure the AOS class is loaded:
>
> java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(JavaThread::current()); 
>
>
> but we don't check if the class actually was successfully loaded! We 
> may have an exception pending due to OOME for example. Because the 
> prologue returns true, the VMOp is posted for the VMThread to execute 
> and when doit() accesses the class that was presumed loaded by the 
> prologue we get NULL and hit the assertion.
>
> Simple fix is to just return false if an exception is pending.
>
> Testing: jprt, tmtools tests (in progress)
>
> Thanks,
> David