[Bug general/4889] New: adding new codeObserver in updateHit causes java.lang.IllegalStateException: Already stepping

["pmachata at redhat dot com" <sourceware-bugzilla@sourceware.org>]

FC6.

Adding new codeObserver in updateHit causes java.lang.IllegalStateException:
Already stepping.  The stack trace I'm getting:
Exception in thread "main" java.lang.IllegalStateException: Already stepping
   at frysk.proc.Breakpoint.prepareStep(fltrace)
   at frysk.proc.live.LinuxTaskState$Running.sendContinue(fltrace)
   at frysk.proc.live.LinuxTaskState$Running.handleStoppedEvent(fltrace)
   at frysk.proc.live.LinuxTask.processStoppedEvent(fltrace)
   at frysk.proc.live.LinuxWaitBuilder.stopped(fltrace)
   at frysk.sys.Wait.wait(fltrace)
   at frysk.sys.Wait.waitAll(fltrace)
   at frysk.event.WaitEventLoop.block(fltrace)
   at frysk.event.EventLoop.runEventLoop(fltrace)
   at frysk.event.EventLoop.run(fltrace)
   at frysk.util.Ltrace.trace(fltrace)
   at frysk.bindir.fltrace.run(fltrace)
   at frysk.bindir.fltrace.main(fltrace)

This doesn't seem to happen when requesting observation of already observed
state.  The problem also goes away when I do

      task.requestUnblock(this);
      return Action.BLOCK;

intead of return Action.CONTINUE.  The problem also went away when something
like that was in effect:

      task.getProc().getMainTask().requestAddCodeObserver(this, retAddr);
      System.err.println("[" + task.getTaskId().intValue() + "]");

All this seems to point to the problem of frysk having "enough time" to do the
observer shenanigans, as is suggested by comments on several places.

`retAddr' given above could have been arbitrary, e.g. I tried to enter
0x080483b4, the address of main in my testing binary, so the problems wasn't in
that I'd request breakpoint inside data segment or something.

-- 
           Summary: adding new codeObserver in updateHit causes
                    java.lang.IllegalStateException: Already stepping
           Product: frysk
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: general
        AssignedTo: frysk-bugzilla at sourceware dot org
        ReportedBy: pmachata at redhat dot com
  GCC host triplet: i686-pc-linux-gnu
OtherBugsDependingO 2229
             nThis:


http://sourceware.org/bugzilla/show_bug.cgi?id=4889

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