Re: [PATCH 2/2] kernel32: Set up a guard page at the bottom of the fiber stack.

[Alexandre Julliard]

Zebediah Figura  writes:
> @@ -96,16 +98,19 @@ LPVOID WINAPI CreateFiberEx( SIZE_T stack_commit, SIZE_T stack_reserve, DWORD fl
>          return NULL;
>      }
> - GetSystemInfo(&si);
> - /* FIXME: should use the thread stack allocation routines here */
>    /* some applications try to use more stack than they allocate */
> - stack_reserve = max(stack_reserve, 1024 * 1024);
> - if(!(fiber->stack_allocation = VirtualAlloc( 0, stack_reserve, MEM_COMMIT, PAGE_READWRITE )))
> - stack_reserve = max(stack_reserve, 1024 * 1024 - 3 * si.dwPageSize);
> - if(!(fiber->stack_allocation = VirtualAlloc( 0, stack_reserve + 3 * si.dwPageSize, MEM_COMMIT, PAGE_READWRITE )))
> {
>     HeapFree( GetProcessHeap(), 0, fiber );
>     return NULL;
> }
> - fiber->stack_base  = (char *)fiber->stack_allocation + stack_reserve;
> - fiber->stack_limit = fiber->stack_allocation;
> - VirtualProtect(fiber->stack_allocation, 3 * si.dwPageSize, PAGE_NOACCESS, &prev);
> - fiber->stack_base  = (char *)fiber->stack_allocation + 3 * si.dwPageSize + stack_reserve;
> - fiber->stack_limit = (char *)fiber->stack_allocation + 3 * si.dwPageSize;

Like the FIXME says, this should reuse the thread stack allocation
routines, instead of reinventing them.

Currently it's implemented in virtual_alloc_thread_stack(), but this
could be adapted and exported as RtlCreateUserStack().