maple_tree: make mas_validate_limits() check root node and node limit

Update mas_validate_limits() to check root node, check node limit pivot if
there is enough room for it to exist and check data_end.  Remove the check
for child existence as it is done in mas_validate_child_slot().

Link: https://lkml.kernel.org/r/20230711035444.526-6-zhangpeng.00@bytedance.com
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index af8fb75ad68866b6c9e827225d2b9f4e36112086..31ac4f2c4426443fd330bd223834fb8d7f952427 100644 (file)
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -7120,7 +7120,9 @@ static void mas_validate_child_slot(struct ma_state *mas)
 }
 
 /*
- * Validate all pivots are within mas->min and mas->max.
+ * Validate all pivots are within mas->min and mas->max, check metadata ends
+ * where the maximum ends and ensure there is no slots or pivots set outside of
+ * the end of the data.
  */
 static void mas_validate_limits(struct ma_state *mas)
 {
@@ -7130,26 +7132,15 @@ static void mas_validate_limits(struct ma_state *mas)
        void __rcu **slots = ma_slots(mte_to_node(mas->node), type);
        unsigned long *pivots = ma_pivots(mas_mn(mas), type);
 
-       /* all limits are fine here. */
-       if (mte_is_root(mas->node))
-               return;
-
        for (i = 0; i < mt_slots[type]; i++) {
                unsigned long piv;
 
                piv = mas_safe_pivot(mas, pivots, i, type);
 
-               if (!piv && (i != 0))
-                       break;
-
-               if (!mte_is_leaf(mas->node)) {
-                       void *entry = mas_slot(mas, slots, i);
-
-                       if (!entry)
-                               pr_err("%p[%u] cannot be null\n",
-                                      mas_mn(mas), i);
-
-                       MT_BUG_ON(mas->tree, !entry);
+               if (!piv && (i != 0)) {
+                       pr_err("Missing node limit pivot at %p[%u]",
+                              mas_mn(mas), i);
+                       MAS_WARN_ON(mas, 1);
                }
 
                if (prev_piv > piv) {
@@ -7172,6 +7163,13 @@ static void mas_validate_limits(struct ma_state *mas)
                if (piv == mas->max)
                        break;
        }
+
+       if (mas_data_end(mas) != i) {
+               pr_err("node%p: data_end %u != the last slot offset %u\n",
+                      mas_mn(mas), mas_data_end(mas), i);
+               MT_BUG_ON(mas->tree, 1);
+       }
+
        for (i += 1; i < mt_slots[type]; i++) {
                void *entry = mas_slot(mas, slots, i);