[ros-dev] Re: [ros-diffs] [navaraf] 17604: Check for Request == NULL.

[Hartmut Birr]

navaraf(a)svn.reactos.com wrote:

>  Check for Request == NULL.
>
> Modified: trunk/reactos/ntoskrnl/lpc/reply.c
>   
>
>  ------------------------------------------------------------------------
>  *Modified: trunk/reactos/ntoskrnl/lpc/reply.c*
>
> --- trunk/reactos/ntoskrnl/lpc/reply.c	2005-09-02 11:29:40 UTC (rev 17603)
> +++ trunk/reactos/ntoskrnl/lpc/reply.c	2005-09-02 13:12:44 UTC (rev 17604)
> @@ -263,6 +263,12 @@
>
>     Request = EiDequeueMessagePort(Port);
>     KeReleaseSpinLock(&Port->Lock, oldIrql);
>  
>   
>
> +   if (Request == NULL)
> +     {
> +       ObDereferenceObject(Port);
> +       return STATUS_UNSUCCESSFUL;
> +     }
> +
>   
>
>     if (Request->Message.u2.s2.Type == LPC_CONNECTION_REQUEST)
>       {
>         PORT_MESSAGE Header;
>   
>  
Hi,

I think that this fix doesn't solve the real problem. The caller waits
on a semaphore and the semaphore is only signaled if a message is in the
queue. This means, the caller can't get a NULL pointer from
EiDequeueMessagePort(). The real problem is anywhere in
KeWaitForSingleObject, which does return STATUS_USER_APC for a non
alertable wait. That is wrong.

- Hartmut