2 files changed, 64 insertions, 0 deletions

diff --git a/tools/testing/radix-tree/multiorder.c b/tools/testing/radix-tree/multiorder.c
index 59245b3d587c..7bf405638b0b 100644
--- a/tools/testing/radix-tree/multiorder.c
+++ b/tools/testing/radix-tree/multiorder.c
@@ -16,6 +16,7 @@
 #include <linux/radix-tree.h>
 #include <linux/slab.h>
 #include <linux/errno.h>
+#include <pthread.h>
 
 #include "test.h"
 
@@ -624,6 +625,67 @@ static void multiorder_account(void)
         item_kill_tree(&tree);
 }
 
+bool stop_iteration = false;
+
+static void *creator_func(void *ptr)
+{
+        /* 'order' is set up to ensure we have sibling entries */
+        unsigned int order = RADIX_TREE_MAP_SHIFT - 1;
+        struct radix_tree_root *tree = ptr;
+        int i;
+
+        for (i = 0; i < 10000; i++) {
+                item_insert_order(tree, 0, order);
+                item_delete_rcu(tree, 0);
+        }
+
+        stop_iteration = true;
+        return NULL;
+}
+
+static void *iterator_func(void *ptr)
+{
+        struct radix_tree_root *tree = ptr;
+        struct radix_tree_iter iter;
+        struct item *item;
+        void **slot;
+
+        while (!stop_iteration) {
+                rcu_read_lock();
+                radix_tree_for_each_slot(slot, tree, &iter, 0) {
+                        item = radix_tree_deref_slot(slot);
+
+                        if (!item)
+                                continue;
+                        if (radix_tree_deref_retry(item)) {
+                                slot = radix_tree_iter_retry(&iter);
+                                continue;
+                        }
+
+                        item_sanity(item, iter.index);
+                }
+                rcu_read_unlock();
+        }
+        return NULL;
+}
+
+static void multiorder_iteration_race(void)
+{
+        const int num_threads = sysconf(_SC_NPROCESSORS_ONLN);
+        pthread_t worker_thread[num_threads];
+        RADIX_TREE(tree, GFP_KERNEL);
+        int i;
+
+        pthread_create(&worker_thread[0], NULL, &creator_func, &tree);
+        for (i = 1; i < num_threads; i++)
+                pthread_create(&worker_thread[i], NULL, &iterator_func, &tree);
+
+        for (i = 0; i < num_threads; i++)
+                pthread_join(worker_thread[i], NULL);
+
+        item_kill_tree(&tree);
+}
+
 void multiorder_checks(void)
 {
         int i;
@@ -644,6 +706,7 @@ void multiorder_checks(void)
         multiorder_join();
         multiorder_split();
         multiorder_account();
+        multiorder_iteration_race();
 
         radix_tree_cpu_dead(0);
 }
diff --git a/tools/testing/radix-tree/test.h b/tools/testing/radix-tree/test.h
index 8cf4a7a7f94c..31f1d9b6f506 100644
--- a/tools/testing/radix-tree/test.h
+++ b/tools/testing/radix-tree/test.h
@@ -13,6 +13,7 @@ struct item {
 struct item *item_create(unsigned long index, unsigned int order);
 int __item_insert(struct radix_tree_root *root, struct item *item);
 int item_insert(struct radix_tree_root *root, unsigned long index);
+void item_sanity(struct item *item, unsigned long index);
 int item_insert_order(struct radix_tree_root *root, unsigned long index,
                         unsigned order);
 int item_delete(struct radix_tree_root *root, unsigned long index);