Fix descent into unnecessary indices

629bd9a9 · David Benjamin · 89c11d1a · 629bd9a9
--- a/kernel/radix.cc
+++ b/kernel/radix.cc
@@ -78,9 +78,9 @@ update_range(radix_entry cur, radix_ptr *ptr, CB cb,
             u64 start, u64 end, u32 level = radix_levels)
 {
  assert(level_size(level) == cur_end - cur_start);
-  // If ranges are disjoint, do nothing.
-  if (cur_start >= end || start >= cur_end)
-    return;
+  // Assert that our ranges intersect; if this fails, we got the loop
+  // below wrong.
+  assert(cur_start < end && start < cur_end)

  // If our range is not strictly contained in the target, ensure we
  // are at a node.
@@ -96,7 +96,7 @@ update_range(radix_entry cur, radix_ptr *ptr, CB cb,
    int i = index(start, level - 1);
    u64 child_size = (cur_end - cur_start) >> bits_per_level;
    u64 child_start = cur_start + i * child_size;
-    for (; (i < (1<<bits_per_level)) && (child_start < cur_end);
+    for (; (i < (1<<bits_per_level)) && (child_start < end);
         i++, child_start += child_size) {
      radix_ptr *child = &cur.node()->child[i];
      update_range(child->load(), child, cb,