A customer has found hang in malloc/free thread in JRE1.4.2 for
RHEL AS3 (IA64).

---- Thread Dump ----
.........

Thread 2 (Thread 2305843010565911168 (LWP 2829)):

#0 0xa000000000010641 in ?? ()
#1 0x2000000000270ef0 in __lll_lock_wait () from /lib/tls/libc.so.6.1
#2 0x2000000000186b00 in free () from /lib/tls/libc.so.6.1
#3 0x2000000000d8f830 in os::free () from /tmp/c/fjvm142_05B11/jre/lib/ia64/fjvm/libjvm.so
#4 0x2000000000e0f350 in PerfMemory::delete_memory_region ()
   from /tmp/c/fjvm142_05B11/jre/lib/ia64/fjvm/libjvm.so
#5 0x2000000000e0d460 in PerfMemory::destroy ()
   from /tmp/c/fjvm142_05B11/jre/lib/ia64/fjvm/libjvm.so
#6 0x2000000000e0d540 in perfMemory_exit () from /tmp/c/fjvm142_05B11/jre/lib/ia64/fjvm/libjvm.so
#7 0x2000000000d94190 in os::abort () from /tmp/c/fjvm142_05B11/jre/lib/ia64/fjvm/libjvm.so
#8 0x2000000000d91780 in os::handle_unexpected_exception ()
   from /tmp/c/fjvm142_05B11/jre/lib/ia64/fjvm/libjvm.so
#9 0x2000000000d9bec0 in JVM_handle_linux_signal ()
   from /tmp/c/fjvm142_05B11/jre/lib/ia64/fjvm/libjvm.so
#10 0x2000000000d974a0 in signalHandler () from /tmp/c/fjvm142_05B11/jre/lib/ia64/fjvm/libjvm.so
#11 <signal handler called>
#12 0x2000000000185800 in _int_free () from /lib/tls/libc.so.6.1
#13 0xc000000000000610 in ?? ()
#14 0x2000000000186a60 in free () from /lib/tls/libc.so.6.1

......
----

According to the above, the hang-up scenario seems as follows.

   Signal generated at free()
   ==> JVM signal handler
   ==> os::abort()
   ==> perfMemory_exit
   ==> free()
   < Here, Hang occurs !! >

As for JRE in Solaris edition, customer works around this issue by checking
whether or not some thread get the lock, "__malloc_lock".
However, they can not apply the same workaround to linux edition
because system library in linux is different from that in Solaris.

###@###.### 2005-03-22 09:30:37 GMT