From: Roddy, Mark [Mark.Roddy@stratus.com]
Sent: Thursday, May 02, 2002 4:16 PM
To: NT Developers Interest List
Subject: [ntdev] RE: Sharing stack-allocated data between threads

I mean that the following is commonplace.

THREAD1:

foo()
{
	KEVENT event; // on the stack, yes?

	.
	.
	KeInitializeEvent(&event,...);
	
	IoSetCompletionRoutine(Irp, fooComplete, &event, ...);

	IoCallDriver(LowerDevObj, Irp);

	KeWaitForSingleObject(&event, ...);

	.
	.
}


SOME OTHER THREAD:
fooComplete(IN PDEVICE_OBJECT  DeviceObject,
    IN PIRP  Irp,
    IN PVOID  Context // this is a pointer to some thread's stack!
    )
{

	.
	.
	.
	KeSetEvent((PRKEVENT)Context, ...);
	.
	.
	return STATUS_MORE_PROCESSING_REQUIRED;
}
    
> -----Original Message-----
> From: int3 [mailto:kssatish@aalayance.com] 
> Sent: Thursday, May 02, 2002 1:22 PM
> To: NT Developers Interest List
> Subject: [ntdev] RE: Sharing stack-allocated data between threads
> 
> 
> Can u explain bit more please.
> 
> ----- Original Message -----
> From: "Roddy, Mark" <Mark.Roddy@stratus.com>
> To: "NT Developers Interest List" <ntdev@lists.osr.com>
> Sent: Thursday, May 02, 2002 10:32 PM
> Subject: [ntdev] RE: Sharing stack-allocated data between threads
> 
> 
> > Actually it is done frequently. For example, a stack allocated event
> object
> > may be used as IO completion context. You do have to be 
> very careful 
> >that  the owning thread's stack is not paged out if the users can be 
> >running at =  DISPATCH_LEVEL.
> >
> >
> >
> > -----Original Message-----
> > From: int3 [mailto:kssatish@aalayance.com]
> > Sent: Thursday, May 02, 2002 12:44 PM
> > To: NT Developers Interest List
> > Subject: [ntdev] RE: Sharing stack-allocated data between threads
> >
> >
> > No, You cannot - I am sure, u will screw me, if u use my 
> thread stack 
> > :-)
> >
> > ----- Original Message -----
> > From: Chtchetkine, Vladimir
> > To: NT Developers Interest List
> > Sent: Thursday, May 02, 2002 9:46 PM
> > Subject: [ntdev] RE: Sharing stack-allocated data between threads
> >
> >
> > Nope! I'm refering to KM thread stack.
> > -----Original Message-----
> > From: Paul Bunn [mailto:Paul@UltraBac.com]
> > Sent: Thursday, May 02, 2002 8:54 AM
> > To: NT Developers Interest List
> > Subject: [ntdev] RE: Sharing stack-allocated data between threads
> >
> >
> > I'm assuming you're refering to user-mode.
> > Since all memory in a process is shared between all threads of that
> process,
> > the stacks all share the same process memory so you can 
> "get at" other 
> > threads' memory.  However, there is the obvious problem that if a 
> > function returns all its stack data is invalidated and be 
> overwritten 
> > by the next stack usage.  So, the answer is "yes, if you're very 
> > careful". Regards Paul Bunn, UltraBac Software, 425-644-6000
> > Microsoft MVP - NT/Windows 2000/XP
> > http://www.ultrabac.com
> >
> >
> > -----Original Message-----
> > From: Chtchetkine, Vladimir 
> [mailto:vladimir.chtchetkine@starbase.com]
> > Sent: Thursday, 
> May 02, 2002 7:23 AM
> > To: NT Developers Interest List
> > Subject: [ntdev] Sharing stack-allocated data between threads
> >
> >
> > Hi everyone!
> > It's a kind of paranoid question, but can I share 
> stack-allocated data 
> > between different threads? I mean can thread stack be 
> viewed as "just 
> > another pool" of memory that is available from all other
> > threads?
> > Sorry, I guess it's been too much of work and beer yesterday :-)
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