Re: [PATCH 2/2 v2] ntdll: Zero debug registers after thread creation

[Christian Inci]

Thanks, I weren't sure about that one. I thought that every recent compiler will zero-initialize local variables/structures.
Are there compilers or some special cases which wouldn't let that happen?
Are they often enough not explicit set to zero (by using non-previously-used memory for the first time), so it'll be assumed to be zero?

On 04/07/2017 06:43 PM, Michael Müller wrote:
> Am 07.04.2017 um 17:52 schrieb Christian Inci:
> >  DWORD tid = 0;
> >  int request_pipe[2];
> > -
> >
> > CONTEXT ctx;
> > NTSTATUS status;
> >
> > [...]
> > -
> >
> > ctx.ContextFlags = CONTEXT_DEBUG_REGISTERS;
> > -
> >
> > NtSetContextThread(handle, &ctx);
> > -
>
> You didn't initialize the register values and therefore set the debug
> registers to random stack values. You should either initialize them
> manually or memset the whole struct.