With Mustang b28, VMark and VTest failed on solaris amd platforms with 64 bits JVM.
Test machine: jtg-sunfire-3
VMark failed after 30 minutes with mustang b28.
# uname -a
SunOS jtg-sunfire-3 5.10 Generic i86pc i386 i86pc
Flags used: -d64 -XX:+UseSerialGC -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+ShowMessageBoxOnError -XX:+PrintGCTimeStamps
/usr/j2se/bin/java -d64 -version
java version "1.6.0-ea"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.6.0-ea-b28)
Java HotSpot(TM) 64-Bit Server VM (build 1.6.0-ea-b28, mixed mode)

I grab libjvm from /net/prt-archiver.sfbay/data/archived_workspaces/main/c2_baseline/2005/20050319123751.rasbold.main_to_c2_baseline/solaris_amd64_compiler2/product/libjvm.so.gz and retested, the problem still happened after 17 minutes.
/usr/mustang_b28/bin/java -d64 -version
java version "1.6.0-ea"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.6.0-ea-b28)
Java HotSpot(TM) 64-Bit Server VM (build 20050319123751.rasbold.main_to_c2_baseline, mixed mode)

Stack trace:
current thread: t@2
=>[1] ___nanosleep(0xfffffd7ffb3fc790, 0xfffffd7ffb3fc780, 0xfffffd7fff32b32c, 0xfffffd7fff33a7fa, 0x0, 0x4f), at 0xfffffd7fff339aba
  [2] _sleep(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7fff32b340
  [3] os::message_box(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7ffefd1dec
  [4] VMError::show_message_box(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7fff028f84
  [5] VMError::report_and_die(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7fff028c10
  [6] JVM_handle_solaris_signal(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7ffebc3ada
  [7] signalHandler(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7ffebc3c40
  [8] __sighndlr(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7fff337e86
  [9] call_user_handler(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7fff32d312
  [10] sigacthandler(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7fff32d4f8
  ---- called from signal handler with signal 11 (SIGSEGV) ------
  [11] memcpy(0xfffffd7fb24e9ae8, 0xfffffd7f78200000, 0xce9e0, 0xeee, 0x0, 0x1000), at 0xfffffd7fff2ba9a9
  [12] Copy::pd_disjoint_words(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7ffeb2fe9b
  [13] Generation::promote(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7ffee26e2b
  [14] DefNewGeneration::copy_to_survivor_space(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7ffee0eaa8
  [15] FastScanClosure::do_oop(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7ffee0f875
  [16] InterpretedArgumentOopFinder::set(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7ffee1f1f4
  [17] SignatureInfo::do_object(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7ffeb8306a
  [18] SignatureIterator::parse_type(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7ffeb4bc07
  [19] SignatureIterator::iterate_parameters(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7ffeb70385
  [20] frame::oops_interpreted_arguments_do(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7ffed2ac7f
  [21] frame::oops_interpreted_do(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7ffeb7eb68
  [22] frame::oops_do_internal(0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0xfffffd7ffb3fd8a0, 0x45dae0, 0xfffffd7ffb3fd858), at 0xfffffd7ffeb4df57
  [23] JavaThread::oops_do(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7ffeb8a716
  [24] Threads::oops_do(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7ffec54c9d
  [25] GenCollectedHeap::process_strong_roots(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7ffee22575
  [26] DefNewGeneration::collect(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7ffee0e3f7
  [27] GenCollectedHeap::do_collection(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7ffee22165
  [28] TwoGenerationCollectorPolicy::satisfy_failed_allocation(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7ffedef9ac
  [29] GenCollectedHeap::satisfy_failed_allocation(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7ffee22497
  [30] VM_GenCollectForAllocation::doit(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7fff02943d
  [31] VM_Operation::evaluate(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7ffebfc9f4
  [32] VMThread::evaluate_operation(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7ffebfcb9e
  [33] VMThread::loop(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7ffed80ef0
  [34] VMThread::run(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7ffed8041b
  [35] _start(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7ffecb2418
  [36] _thr_setup(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7fff337b4b
  [37] _lwp_start(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0xfffffd7fff337d80

###@###.### 2005-03-21 23:21:39 GMT