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

[Hartmut Birr]

navaraf at 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