[ros-kernel] crash within MmOpenMemoryAreaByAddress

[Hartmut B. <har...@te...>]

Hi,

sometimes ros does crash with assertions from MmOpenMemoryAreaByAddress. 
Normaly this can not occur because the address space is locked at any 
operation that will manipulate it. This does not work for recursive calls 
from the same thread, because the lock is a MUTEX. For testing I've it 
changed to a FAST_MUTEX and do print out the calling functions and the 
stack trace (KeBugCheck does this) at a recursive call from the same 
thread. A simple test with 'gcc -o rdel.o rdel.c -c -pipe' crashs ros. The 
recursive functions are MmUnmapLockedPages and MmMapLockedPages. It seems, 
that a locked address space also must disable the task switching. For 
testing, I've added a KeRaiseIrql/KeLowerIrql at each lock/unlock for the 
kernel address space. This solve the problem. I think we must change the 
handling for address spaces and memory areas. At many points, where the 
address space is locked (access and paging faults), there must be locked 
the memory area from the address space and not the address space itself. 
All changes within the address space must occur without thread switching 
(irql raise to DISPATCH_LEVEL). Some functions must be split for a short 
lock time of address spaces (MmFreeMemoryArea).

Any ideas or comments?

- Hartmut