atg server crashed on j2se-b.west with CMS collector with fastdebug build from main baseline.
j2se-b# uname -a
SunOS j2se-b 5.10 Generic_118822-15 sun4u sparc SUNW,Sun-Fire
j2se-b# /usr/j2se/bin/java -version
java version "1.6.0-ea"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.6.0-ea-b48)
Java HotSpot(TM) Server VM (build 20050825070300.mingyao.rt_merge-debug, mixed mode)

flags used: -server -XX:+UseConcMarkSweepGC
-XX:+CMSClassUnloadingEnabled -XX:+CMSPermGenSweepingEnabled
-XX:+DeoptimizeALot -XX:+SafepointALot

Error message:
# after -XX: or in .hotspotrc: SuppressErrorAt=/mutexLocker.cpp:99]
==============================================================================
Unexpected Error
------------------------------------------------------------------------------
Internal Error at mutexLocker.cpp:99, pid=3978, tid=20

Stack retrace:
(dbx) where
current thread: t@20
=>[1] ___nanosleep(0xf9d7f420, 0xf9d7f418, 0x10, 0x0, 0xff0a3c9b,
0x6dc), at 0xff33f6c8
  [2] sleep(0x64, 0xf9d7f4a8, 0x0, 0x0, 0x0, 0x0), at 0xff3328f0
  [3] os::message_box(0xfef6e866, 0xff0a3ba8, 0xf9d7f4a8, 0x4e,
0xf9d7f4b8, 0x64), at 0xfe034d00
  [4] VMError::show_message_box(0xf9d7f698, 0xff0a3ba8, 0x7d0, 0x2a800,
0x36, 0xfeff0494), at 0xfe326ca0
  [5] VMError::report_and_die(0xf9d7f698, 0x30c00, 0x31c00, 0xff0a4380,
0xff05ffb4, 0xff0a4378), at 0xfe3256c0
  [6] report_fatal_vararg(0xfec4f63a, 0x63, 0xff05ff8d, 0xfeff0494,
0x30e80, 0x30c00), at 0xfd85c7b8
  [7] assert_locked_or_safepoint(0x2153c, 0x0, 0xff0602dc, 0xfeff0494,
0x2ead4, 0x21400), at 0xfdfd2f24
  [8] ConcurrentMarkSweepGeneration::grow_by(0x17c318, 0x980000,
0xff07af34, 0x17c33c, 0xfeff0494, 0x33000), at 0xfd808efc
  [9] ConcurrentMarkSweepGeneration::compute_new_size(0x97fcf2,
0x17c318, 0xa000, 0x2e7c4, 0xa000, 0xfd7febe0), at 0xfd7ff0e8
  [10] CMSCollector::collect_in_background(0xff07e9b4, 0x1fca08,
0x57798, 0x578e0, 0xfbf98, 0xfbe10), at 0xfd804074
  [11] ConcurrentMarkSweepThread::run(0x1, 0x39e80, 0x31800, 0x39e80,
0x28db00, 0xfeff0494), at 0xfd828c78
  [12] java_start(0x28db00, 0x2, 0xff07f2fc, 0x22400, 0xfeff0494,
0x28e8f0), at 0xfe02d958

I also ran atg with ParallelGC on a similiar solaris sparc machine
j2se-a.west, the test went well with Parallel GC.

I am rerunning the test on a similiar machine to find out how easy or difficult to reproduce the bug.


How to reproduce the bug:
1. log on to j2se-b.west
2. export JAVA_HOME=<your java home>
3. export STARTLOOP=20 ( default value is 10 )
3. /bs/runatg.ksh -server -XX:+UseConcMarkSweepGC -XX:+CMSClassUnloadingEnabled -XX:+CMSPermGenSweepingEnabled -XX:+DeoptimizeALot -XX:+SafepointALot
4. log files will be located under /bt/atg*, server log is "atgserver.log"