Re: determining process context

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Does that mean, when it runs under system process context it is
essentially same "Application" process context by which this dispatch
routine is called?
Reason of this question is, I need to access buffer pointer from IRP
which has User virtual address and in order to access that, i need to
be in same process context else i will corrupt some memory.
So am i doing it correctly by running PsCreateSystemThread in system
process context ? if not, what do I need to do to achieve this?

- David



cristalink wrote:
> >> Is my Thread running in the same process context where Irp buffer belongs
>
> PsCreateSystemThread has nothing to do with IRPs. The process context of the
> created thread depends on the 4th parameter of PsCreateSystemThread. As per
> DDK documentation, you should use NULL for the 4th parameter. If you do,
> then the thread will run in the system process context.
> --
> http://www.cristalink.com
>
>
> "David" <know_devig@xxxxxxxxxxx> wrote in message
> news:1122086162.688945.164730@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> > Hi,
> > I am developing WDM driver and curious about process context.
> >
> > 1) My Application calls DeviceIoControl.
> > 2) My Driver's Dispatch routine gets invoked, in this routine I start
> > thread using PsCreateSystemThread. ( Which waits on syncronization
> > objects)
> > 3) Once Interrupt (or synchronization event) happens, this thread
> > wakes up and start processing pending IRP.
> >
> > So question is ->
> > 1) Is my Thread running in the same process context where Irp buffer
> > belongs? Because I need to lock the buffer and write some data to it,
> > (I am using METHODE_NEITHER)
> >
> > Thanks,
> > David
> >

.

Relevant Pages

  • Re: determining process context
    ... when it runs under system process context it is ... > essentially same "Application" process context by which this dispatch ... > routine is called? ... Don Burn (MVP, Windows DDK) ...
    (microsoft.public.development.device.drivers)
  • Re: METHOD_OUT_DIRECT and MmGetSystemAddressForMdlSafe
    ... There is no requirement to be in the process context. ... routine and processed later by a kernel worker thread, ... the calling process? ...
    (microsoft.public.development.device.drivers)
  • Re: context of irp_mj_close
    ... IRP_MJ_CLOSE is sent when a last reference to FILE_OBJECT is closed. ... each IRP originating from user ... process context. ... > the context of this process object. ...
    (microsoft.public.development.device.drivers)