A problem with startUp messages

Rob Withers rwithers12 at mediaone.net
Thu Jun 28 04:12:14 UTC 2001

Just ignore my previous post, please.  Imagine a computer that wasn't
completely booting and here I am asking if it's been plugged in.  "Is it that
thingy causing the problem?"  :-)

On Wed, 27 Jun 2001, Rob Withers wrote:
> Hi Kevin,
> Is there a signal handler being installed for SIGCHLD, in the vm?  The default
> action (SIG_DFL) is to ignore the signal.  I thought the child PID goes
> zombie as a result, but I couldn't find evidence in the man pages..    
> Rob
> On Wed, 27 Jun 2001, Kevin
> Fisher wrote: > Hi folks:
> > 
> > I've been working with David Lewis, trying to figure out why OSProcess has 
> > been leaving behind <defunct> zombie processes.  It turns out, the problem 
> > isn't with OSProcess at all...
> > 
> > In my image, the SystemDictionary's StartUpList has UnixOSProcessAccessor 
> > later in the ordered collection, after SecurityManager.  When the image gets 
> > restarted, only classes iterated over the StartUpList up to and including 
> > SecurityManager receive the startUp message.  After that, SystemDictionary>>
> > send:toClassesNamedIn:with: terminates prematurely, leaving several classes 
> > not restarted (including UnisOSProcessAccessor, the source of the OSProcess 
> > zombies).  Actually I'm not sure it terminates at all, it seems to get stuck 
> > at SecurityManager.
> > 
> > It looks as though SecurityManager class>>startUp never returns...but only 
> > during startup.  Once the image is up and running, doing a SecurityManager 
> > startUp seems to work just fine...it's only during the startup that something 
> > funny happens.  The trick is to put Transcript show: scaffolding around 'self 
> > default startUp' in SecurityManager class>>startUp...open a Transcript, save 
> > the image and quit, reload and watch what gets put in the Transcript.  The 
> > first Transcript show: will appear, but the second does not.  However, once 
> > the image is up, doing a SecurityManager startUp will show both Transcript 
> > show: 's.  Perhaps some sort of deadlock is happening during the restart of 
> > the image?
> > 
> > I'm a bit stumped at this point...any ideas?  This is on the UNIX VM, with the 
> > latest changes in the 3.1 image.

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