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, 28 insertions, 0 deletions

diff --git a/rust/helpers/refcount.c b/rust/helpers/refcount.c
new file mode 100644
index 000000000..36334a674
--- /dev/null
+++ b/rust/helpers/refcount.c
@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/refcount.h>
+
+__rust_helper refcount_t rust_helper_REFCOUNT_INIT(int n)
+{
+	return (refcount_t)REFCOUNT_INIT(n);
+}
+
+__rust_helper void rust_helper_refcount_set(refcount_t *r, int n)
+{
+	refcount_set(r, n);
+}
+
+__rust_helper void rust_helper_refcount_inc(refcount_t *r)
+{
+	refcount_inc(r);
+}
+
+__rust_helper void rust_helper_refcount_dec(refcount_t *r)
+{
+	refcount_dec(r);
+}
+
+__rust_helper bool rust_helper_refcount_dec_and_test(refcount_t *r)
+{
+	return refcount_dec_and_test(r);
+}