[Help-smalltalk] JIT user interrupts and updating the context

[Holger Hans Peter Freyther]

Dear Paolo,

I get a NULL pointer dereference when using CTRL+C on the below piece
of code in unwind_context but I think the error might happen earlier
or for the same reason

 st>  [[(Delay forSeconds: 3) wait. '123' printNl] repeat] value
=> CTRL+C

MessageNotUnderstood(Exception)>>signal (ExcHandling.st:254)
UndefinedObject(Object)>>doesNotUnderstand: #goodness: (SysExcept.st:1408)
optimized [] in BlockClosure class>>exceptionHandlerSearchBlock 
(BlkClosure.st:16)
[] in SystemExceptions.UserInterrupt(Exception)>>instantiateNextHandlerFrom: 
(ExcHandling.st:340)
MethodContext(ContextPart)>>scanBacktraceForAttribute:do: (ContextPart.st:578)
SystemExceptions.UserInterrupt(Exception)>>instantiateNextHandlerFrom: 
(ExcHandling.st:342)
SystemExceptions.UserInterrupt(Exception)>>signal (ExcHandling.st:254)
SystemExceptions.UserInterrupt class(Exception class)>>signal 
(ExcHandling.st:151)
ProcessorScheduler(Object)>>userInterrupt (Object.st:1398)
optimized [] in Delay class>>initialize (Delay.st:196)
[] in Process>>onBlock:at:suspend: (Process.st:412)
BlockClosure>>on:do: (BlkClosure.st:196)
[] in Process>>onBlock:at:suspend: (Process.st:413)
BlockClosure>>ensure: (BlkClosure.st:271)
[] in Process>>onBlock:at:suspend: (Process.st:391)
[] in BlockClosure>>asContext: (BlkClosure.st:182)
BlockContext class>>fromClosure:parent: (BlkContext.st:68)
lt-gst: interp.c:1035: unwind_context: Assertion `newContextOOP != ((void *)0)' 
failed.
stdin:2: Aborted
(ip 12)BlockContext class>>#fromClosure:parent:
Aborted (core dumped)

As usual I don't understand the issue yet. The interrupt should be
queued through a normal SET_EXCEPT_FLAG and all frame information
should be written back. Do you have an idea or time to look into for
a fix?

holger