To reproduce this bug, run the regression test

  test/java/awt/Dialog/HideDialogTest/HideDialogTest.html

(The test has also been attached to this bug for convenience.)

Click the "test" button to show the modal dialog, and then click the "dismiss-
with-dispose" button. You will need to repeat this about 50 times to see the
following crash:

Xt error
SIGSEGV 11* segmentation violation
    si_signo [11]: SIGSEGV 11* segmentation violation
    si_errno [0]: Error 0
    si_code [1]: SEGV_MAPERR [addr: 0x154]

        stackbase=EDDF2000, stackpointer=EDDF0FD0

Full thread dump:
    "Screen Updater" (TID:0xee314680, sys_thread_t:0xeddc1db8, state:CW) prio=4
        java.lang.Object.wait(Object.java)
        sun.awt.ScreenUpdater.nextEntry(ScreenUpdater.java:70)
        sun.awt.ScreenUpdater.run(ScreenUpdater.java:90)
    "AWT-Motif" (TID:0xee312640, sys_thread_t:0xeddf1db8, state:R) prio=5: pending=java.lang.NullPointerException *current thread*
        java.lang.Thread.run(Thread.java)
    "AWT-Input" (TID:0xee312660, sys_thread_t:0xedfc1db8, state:CW) prio=5
    "AWT-EventQueue-0" (TID:0xee312678, sys_thread_t:0xedff1db8, state:CW) prio=5
        java.lang.Object.wait(Object.java)
        java.awt.EventQueue.getNextEvent(EventQueue.java:118)
        java.awt.EventDispatchThread.run(EventDispatchThread.java:67)
    "thread applet-HideDialogTest" (TID:0xee311b00, sys_thread_t:0xef2c1db8, state:CW) prio=4
        java.lang.Object.wait(Object.java)
        sun.applet.AppletPanel.getNextEvent(AppletPanel.java:214)
        sun.applet.AppletPanel.run(AppletPanel.java:238)
        java.lang.Thread.run(Thread.java)
    "Finalizer thread" (TID:0xee300210, sys_thread_t:0xef2f1db8, state:CW) prio=1
    "Async Garbage Collector" (TID:0xee300258, sys_thread_t:0xef3f1db8, state:R) prio=1
    "Idle thread" (TID:0xee3002a0, sys_thread_t:0xef4c1db8, state:R) prio=0
    "Clock" (TID:0xee300088, sys_thread_t:0xef4f1db8, state:CW) prio=12
    "main" (TID:0xee3000b0, sys_thread_t:0x45f20, state:CW) prio=5
Monitor Cache Dump:
    sun.awt.ScreenUpdater@EE314680/EE381030: <unowned>
        Waiting to be notified:
            "Screen Updater" (0xeddc1db8)
    sun.awt.motif.MToolkit@EE312440/EE379230: owner "AWT-Motif" (0xeddf1db8, 1 entry)
        Waiting to be notified:
            "AWT-Input" (0xedfc1db8)
    java.awt.EventQueue@EE312410/EE379680: <unowned>
        Waiting to be notified:
            "AWT-EventQueue-0" (0xedff1db8)
    sun.applet.AppletViewerPanel@EE3117E0/EE3764A8: <unowned>
        Waiting to be notified:
            "thread applet-HideDialogTest" (0xef2c1db8)
    <unknown key> (0xef3f1db8): owner "Async Garbage Collector" (0xef3f1db8, 1 entry)
Registered Monitor Dump:
    Thread queue lock: <unowned>
        Waiting to be notified:
            "main" (0x45f20)
    Name and type hash table lock: <unowned>
    String intern lock: <unowned>
    JNI pinning lock: <unowned>
    JNI global reference lock: <unowned>
    BinClass lock: <unowned>
    Class loading lock: <unowned>
    Java stack lock: <unowned>
    Code rewrite lock: <unowned>
    Heap lock: <unowned>
    Has finalization queue lock: <unowned>
    Finalize me queue lock: <unowned>
        Waiting to be notified:
            "Finalizer thread" (0xef2f1db8)
    Dynamic loading lock: <unowned>
    Monitor IO lock: <unowned>
    Child death monitor: <unowned>
    Event monitor: <unowned>
    I/O monitor: <unowned>
    Alarm monitor: <unowned>
        Waiting to be notified:
            "Clock" (0xef4f1db8)
    Sbrk lock: <unowned>
    Monitor registry: owner "AWT-Motif" (0xeddf1db8, 1 entry)
Thread Alarm Q:
Abort (core dumped)

The crash seems to happen only with green threads. A core file has been
attached. Analyzing the core in dbx, we can see that the XEvent structure
has a NIL display. This probably causes the crash in _XtSortPerDisplayList.

This bug may have been introduced by the XPutBack change to awt_Component.c.
We know that this change is wrong for at least one reason: it can cause
out-of-order execution of XEvents. This problem has been fixed in 1.2, but
not in 1.1.7. See the current 1.2 codebase for the corrected implementation.