The JCK test unbind_Unbind001 hangs when exiting on Solaris i486. The call
stack indicates that a set_thread call is made which causes a thread to
hold the malloc lock. The thread holding the lock gets interrupted by a gc
event, it appears. This causes the test to hang. It's intermittent - about
1 in every 20 times, and has been reproduced with a ladybird baseline,
product build, and on a lightly loaded 2 cpu system.

The interesting thread stacks are below. I'll attach an output file of the
dbx session which I've attached to the hanging application.

(dbx) where
current thread: t@21
=>[1] __lwp_sema_wait(0xd52f0d74), at 0xdfaeab46
  [2] _park(), at 0xdfb893ad
  [3] _swtch(), at 0xdfb891d3
  [4] _dopreempt(), at 0xdfb8b366
  [5] _sigsuspnd(), at 0xdfb8d863
  [6] _siglwp(), at 0xdfb8d8a6
  [7] __sighndlr(), at 0xdfb878bf
  [8] sigacthandler(), at 0xdfb958db
  ---- called from signal handler with signal 33 (SIGLWP) ------
  [9] _smalloc(), at 0xdfaf583e
  [10] _malloc_unlocked(), at 0xdfaf5958
  [11] realloc(), at 0xdfaf5a96
  [12] pthread_setspecific(), at 0xdfb91fd6
  [13] os::thread_local_storage_at_put(), at 0xdee2a2d9
  [14] ThreadLocalStorage::set_thread(), at 0xdee5afa2
  [15] Thread::initialize_thread_local_storage(), at 0xdee5690a
  [16] JavaThread::run(), at 0xdee57bb3
  [17] _start(), at 0xdee29905

and

(dbx) where t@17
current thread: t@17
=>[1] _swtch(0x0), at 0xdfb892ab
  [2] _mutex_adaptive_lock(0x804e900), at 0xdfb8a682
  [3] _cmutex_lock(0x804e900), at 0xdfb8a4ac
  [4] Mutex::wait_for_lock_implementation(0x804e8d0), at 0xdee1ff5b
  [5] Mutex::lock_without_safepoint_check(0x804e8d0), at 0xdee1fd28
  [6] SafepointSynchronize::block(0x8156c70), at 0xdee398be
  [7] ObjectMonitor::wait(0x80f4634), at 0xdee24d5b
  [8] ObjectSynchronizer::wait(0x81535d0), at 0xdee448a9
  [9] JVM_MonitorWait(0x8156cf4), at 0xdedeea43
  [10] 0x8099ca3(0x0), at 0x8099ca2
  [11] 0x8096fdc(0x0), at 0x8096fdb
  [12] 0x8097094(0x0), at 0x8097093
  [13] 0x80971a8(0xd5862ab8), at 0x80971a7
  [14] 0xdefed2d6(0xd5430b64), at 0xdefed2d5
  [15] JavaCalls::call_helper(0xd5430cdc), at 0xdedd6cd8
  [16] os::os_exception_wrapper(0xdedd6b88), at 0xdee2b46f
  [17] JavaCalls::call(0xd5430cdc), at 0xdedd6b7b
  [18] JavaCalls::call_virtual(0xd5430cdc), at 0xdedd6514
  [19] JavaCalls::call_virtual(0xd5430cdc), at 0xdedd6595
  [20] thread_entry(0x8156c70), at 0xdedf555d
  [21] JavaThread::thread_main_inner(0x8156c70), at 0xdee57c70
  [22] JavaThread::run(0x8156c70), at 0xdee57c1b
  [23] _start(0x8156c70), at 0xdee29905

(dbx) where t@1
current thread: t@1
=>[1] _swtch(0x0), at 0xdfb892ab
  [2] cond_wait(0x804f4c8), at 0xdfb880ef
  [3] Monitor::wait(0x804f480), at 0xdee20e76
  [4] VMThread::execute(0x8046354), at 0xdee65f61
  [5] os::exit(0x5f), at 0xdee2a527
  [6] vm_exit(0x5f), at 0xdedd5c69
  [7] JVM_Halt(0x5f), at 0xdedee315
  [8] Java_java_lang_Shutdown_halt(0x80501fc), at 0xdf8edd84
  [9] 0x8099ca3(0xd983c8a8), at 0x8099ca2
  [10] 0x8096fdc(0x0), at 0x8096fdb
  [11] 0x8096fdc(0xd58404b0), at 0x8096fdb
  [12] 0x8096fdc(0x5f), at 0x8096fdb
  [13] 0x8096fdc(0xd58099c8), at 0x8096fdb
  [14] 0x8096fdc(0xd5840348), at 0x8096fdb
  [15] 0xdefed2d6(0x8046534), at 0xdefed2d5
  [16] JavaCalls::call_helper(0x8046698), at 0xdedd6cd8
  [17] os::os_exception_wrapper(0xdedd6b88), at 0xdee2b46f
  [18] JavaCalls::call(0x8046698), at 0xdedd6b7b
  [19] jni_invoke(0x80501fc), at 0xdeddc35d
  [20] jni_CallStaticVoidMethod(0x80501fc), at 0xdede4717
  [21] main(0x4), at 0x8049a05
(dbx) where t@4
current thread: t@4
=>[1] __lwp_sema_wait(0xdf605d74), at 0xdfaeab46
  [2] _park(), at 0xdfb893ad
  [3] _swtch(), at 0xdfb88fe8
  [4] _mutex_adaptive_lock(), at 0xdfb8a682
  [5] _cmutex_lock(), at 0xdfb8a4ac
  [6] SuspendThread_Callback::execute(), at 0xdee2c464
  [7] suspend_thread_impl(), at 0xdee29f42
  [8] os::suspend_thread(), at 0xdee29ff7
  [9] os::suspend_thread_async(), at 0xdee2a019
  [10] VM_Exit::doit(), at 0xdee2c3c9
  [11] VM_Operation::evaluate(), at 0xdee663a5
  [12] VMThread::evaluate_operation(), at 0xdee65b46
  [13] VMThread::loop(), at 0xdee65d41
  [14] VMThread::run(), at 0xdee659ce
  [15] _start(), at 0xdee29905