Peter,
Yeah, race conditions are always a possibility, but in this instance I can’t
see where that would apply. The IRP is sent to the hardware, not hung on any
queues, and not seen again until the hardware interrupts. Since this is a
special request type operation, access to the IRP is very restricted with
only the dispatch routine that sends it to the hardware, the ISR, and the
DPC that completes it ever seeing it.
I just noticed that after sending it to the hardware and the waiting on the
hardware interrupt to complete the IRP, that is waiting without a cancel
routine. Oops, that’s a bug, but that should not affect whether or not
I can acquire a pointer to the current stack location at DIRQL.
Gary G. Little
Sr. Staff Engineer
Broadband Storage, LLC
xxxxx@broadstor.com
xxxxx@delphieng.com
-----Original Message-----
From: Peter Viscarola [mailto:xxxxx@osr.com]
Sent: Wednesday, March 07, 2001 2:46 PM
To: NT Developers Interest List
Subject: [ntdev] Re: [NTDEV] Rules for the use of
IoGetCurrentIrpStackLocation in Windows 2000
“Gary G. Little” wrote in message news:xxxxx@ntdev…
> DISPATCH_LEVEL… I see no reason why IRQL should be a restriction since
all
> IGCISL does is fetch the CurrentStackLocation field in the Tail.Overlay
> structure of the IRP.
>
Me either. This is entirely safe.
>
> However, why are CurrentStackLocation NULL and
> CurrentLocation 4?
>
Ugh. Well, THAT’s a harder question, isn’t it. The ONLY thing I can guess
is an ordinary, garden-variety type bug in your driver. Perhaps you’ve got
a race condition involving this IRP somewhere/somehow? Sorry, Gary, I know
that’s not a very satisfying answer, but that’s all I can think of to
suggest.
There certainly is no problem calling IoGetCurrentIrpStackLocation() from
your ISR.
Peter
OSR
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