HotSpot can deadlock in VM code during intensive parallel class loading.

I was able to manually reproduce the hang with HS20b06/7b126 using "-server -Xcomp -XX:+StartAttachListener -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode" options(Java and native thread dumps are included), but I saw similar hangs during b124/b125 testing with both JIT-compilers (mixed/comp modes):
http://vmsqe.russia.sun.com/execution/results/JDK7/PROMOTION/VM/7/b124/ParallelGC/vm/linux-i586/client/mixed/linux-i586_vm__client_mixed_vm.parallel_class_loading.testlist/analysis.html
http://vmsqe.russia.sun.com/execution/results/JDK7/PROMOTION/VM/7/b125/ConcMarkSweepIncGC/vm/linux-i586/server/comp/linux-i586_vm__server_comp_vm.parallel_class_loading.testlist/analysis.html
http://vmsqe.russia.sun.com/execution/results/JDK7/PROMOTION/VM/7/b125/ConcMarkSweepIncGC/vm/solaris-sparc/server/comp/solaris-sparc_vm__server_comp_vm.parallel_class_loading.testlist/analysis.html