Only the to be protected range needs to be non-wired.

When setting memory protection, only ensure/wait for the range that
needs to be protected to not be wired instead of requiering the whole
area to be non-wired. The memory protection is done page wise and
having some parts of the area wired shouldn't preclude other parts to
be protected.

src/system/kernel/vm/vm.cpp

@@ -6261,15 +6261,6 @@ _user_set_memory_protection(void* _address, size_t size, uint32 protection)
 			if ((area->protection & B_KERNEL_AREA) != 0)
 				return B_NOT_ALLOWED;
 
-			AreaCacheLocker cacheLocker(area);
-
-			if (wait_if_area_is_wired(area, &locker, &cacheLocker)) {
-				restart = true;
-				break;
-			}
-
-			cacheLocker.Unlock();
-
 			// TODO: For (shared) mapped files we should check whether the new
 			// protections are compatible with the file permissions. We don't
 			// have a way to do that yet, though.
@@ -6277,6 +6268,16 @@ _user_set_memory_protection(void* _address, size_t size, uint32 protection)
 			addr_t offset = currentAddress - area->Base();
 			size_t rangeSize = min_c(area->Size() - offset, sizeLeft);
 
+			AreaCacheLocker cacheLocker(area);
+
+			if (wait_if_area_range_is_wired(area, currentAddress, rangeSize,
+					&locker, &cacheLocker)) {
+				restart = true;
+				break;
+			}
+
+			cacheLocker.Unlock();
+
 			currentAddress += rangeSize;
 			sizeLeft -= rangeSize;
 		}