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, 14 insertions, 0 deletions

diff --git a/tools/testing/shared/maple-shim.c b/tools/testing/shared/maple-shim.c
new file mode 100644
index 000000000..16252ee61
--- /dev/null
+++ b/tools/testing/shared/maple-shim.c
@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+/* Very simple shim around the maple tree. */
+
+#include "maple-shared.h"
+#include <linux/slab.h>
+
+#include "../../../lib/maple_tree.c"
+
+void maple_rcu_cb(struct rcu_head *head) {
+	struct maple_node *node = container_of(head, struct maple_node, rcu);
+
+	kmem_cache_free(maple_node_cache, node);
+}