selftests/bpf: Add a test for objects stuck in free_by_rcu_ttracegrafted

Delete all elements of BPF_F_NO_PREALLOC hash map in one batch. The first
free_bulk() starts RCU tasks trace GP and the rest of the elements are
freed while it's in flight. Wait for call_rcu_ttrace_in_progress to clear
in bpf_mem_cache of every cpu and check that free_by_rcu_ttrace and
waiting_for_gp_ttrace lists are empty.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20260930095920.601738-4-alexei.starovoitov@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/rust/helpers/binder.c b/rust/helpers/binder.c
new file mode 100644
index 000000000..a2327f1b3
--- /dev/null
+++ b/rust/helpers/binder.c
@@ -0,0 +1,27 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Copyright (C) 2025 Google LLC.
+ */
+
+#include <linux/list_lru.h>
+#include <linux/task_work.h>
+
+__rust_helper unsigned long rust_helper_list_lru_count(struct list_lru *lru)
+{
+	return list_lru_count(lru);
+}
+
+__rust_helper unsigned long rust_helper_list_lru_walk(struct list_lru *lru,
+						      list_lru_walk_cb isolate,
+						      void *cb_arg,
+						      unsigned long nr_to_walk)
+{
+	return list_lru_walk(lru, isolate, cb_arg, nr_to_walk);
+}
+
+__rust_helper void rust_helper_init_task_work(struct callback_head *twork,
+					      task_work_func_t func)
+{
+	init_task_work(twork, func);
+}