Re: [ros-kernel] CVS commit: ReactOS

[<we...@cw...>]

Quoting Hartmut Birr <har...@te...>:
> 
> If two processes have a not present fault within the same address range,
> there is called MmNotPresentFaultSectionView. The first get the pageop
> and handles the fault. The second use this page, if the event in the pageop
> is signaled. If the first process terminate before the second can map the
> page, than is the page unmapped and not longer valid. There occurs a bug
> check within the following call to MmReferencePage. If gcc uses piping,
> there are started three processes within a short time and two of them
> does also exit at the same time. The page fault occurs within msvcrt.dll when
> __atexit_ptr is accessed from exit. The faulting address is __atexit_ptr. 
> The first fix was to init this variable within DllMain but the real
> problem is in MmNotPresentFaultSectionView.
> 
Ok, thanks for the explanation. I don't think this fixes all the problems
of this type: for example MmNotPresentFaultSectionView doesn't even
reference the section so it could be freed by the time it returns after
waiting for the page operation. The fix I was considering was to check for
pending page operations on a unmap/process exit and either wait for them
to complete or abandon freeing section pages that are about to be used in
another process.