radix-tree tests: add test for radix_tree_iter_next

Without fix test crashes inside tagged iteration.

Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 39 insertions, 8 deletions

diff --git a/tools/testing/radix-tree/regression3.c b/tools/testing/radix-tree/regression3.c
index 17d3ba5f4a0a..1f06ed73d0a8 100644
--- a/tools/testing/radix-tree/regression3.c
+++ b/tools/testing/radix-tree/regression3.c
@@ -5,6 +5,10 @@
  * In following radix_tree_next_slot current chunk size becomes zero.
  * This isn't checked and it tries to dereference null pointer in slot.
  *
+ * Helper radix_tree_iter_next reset slot to NULL and next_index to index + 1,
+ * for tagger iteraction it also must reset cached tags in iterator to abort
+ * next radix_tree_next_slot and go to slow-path into radix_tree_next_chunk.
+ *
  * Running:
  * This test should run to completion immediately. The above bug would
  * cause it to segfault.
@@ -24,26 +28,27 @@
 void regression3_test(void)
 {
         RADIX_TREE(root, GFP_KERNEL);
-        void *ptr = (void *)4ul;
+        void *ptr0 = (void *)4ul;
+        void *ptr = (void *)8ul;
         struct radix_tree_iter iter;
         void **slot;
         bool first;
 
         printf("running regression test 3 (should take milliseconds)\n");
 
-        radix_tree_insert(&root, 0, ptr);
+        radix_tree_insert(&root, 0, ptr0);
         radix_tree_tag_set(&root, 0, 0);
 
         first = true;
         radix_tree_for_each_tagged(slot, &root, &iter, 0, 0) {
-//              printk("tagged %ld %p\n", iter.index, *slot);
+                printf("tagged %ld %p\n", iter.index, *slot);
                 if (first) {
                         radix_tree_insert(&root, 1, ptr);
                         radix_tree_tag_set(&root, 1, 0);
                         first = false;
                 }
                 if (radix_tree_deref_retry(*slot)) {
-//                      printk("retry %ld\n", iter.index);
+                        printf("retry at %ld\n", iter.index);
                         slot = radix_tree_iter_retry(&iter);
                         continue;
                 }
@@ -52,13 +57,13 @@ void regression3_test(void)
 
         first = true;
         radix_tree_for_each_slot(slot, &root, &iter, 0) {
-//              printk("slot %ld %p\n", iter.index, *slot);
+                printf("slot %ld %p\n", iter.index, *slot);
                 if (first) {
                         radix_tree_insert(&root, 1, ptr);
                         first = false;
                 }
                 if (radix_tree_deref_retry(*slot)) {
-//                      printk("retry %ld\n", iter.index);
+                        printk("retry at %ld\n", iter.index);
                         slot = radix_tree_iter_retry(&iter);
                         continue;
                 }
@@ -67,18 +72,44 @@ void regression3_test(void)
 
         first = true;
         radix_tree_for_each_contig(slot, &root, &iter, 0) {
-//              printk("contig %ld %p\n", iter.index, *slot);
+                printk("contig %ld %p\n", iter.index, *slot);
                 if (first) {
                         radix_tree_insert(&root, 1, ptr);
                         first = false;
                 }
                 if (radix_tree_deref_retry(*slot)) {
-//                      printk("retry %ld\n", iter.index);
+                        printk("retry at %ld\n", iter.index);
                         slot = radix_tree_iter_retry(&iter);
                         continue;
                 }
         }
 
+        radix_tree_for_each_slot(slot, &root, &iter, 0) {
+                printf("slot %ld %p\n", iter.index, *slot);
+                if (!iter.index) {
+                        printf("next at %ld\n", iter.index);
+                        slot = radix_tree_iter_next(&iter);
+                }
+        }
+
+        radix_tree_for_each_contig(slot, &root, &iter, 0) {
+                printf("contig %ld %p\n", iter.index, *slot);
+                if (!iter.index) {
+                        printf("next at %ld\n", iter.index);
+                        slot = radix_tree_iter_next(&iter);
+                }
+        }
+
+        radix_tree_tag_set(&root, 0, 0);
+        radix_tree_tag_set(&root, 1, 0);
+        radix_tree_for_each_tagged(slot, &root, &iter, 0, 0) {
+                printf("tagged %ld %p\n", iter.index, *slot);
+                if (!iter.index) {
+                        printf("next at %ld\n", iter.index);
+                        slot = radix_tree_iter_next(&iter);
+                }
+        }
+
         radix_tree_delete(&root, 0);
         radix_tree_delete(&root, 1);