A problem with startUp messages

Rob Withers rwithers12 at mediaone.net
Thu Jun 28 03:48:49 UTC 2001

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..    


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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