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, 73 insertions, 0 deletions

diff --git a/include/rv/kunit.h b/include/rv/kunit.h
new file mode 100644
index 000000000..31e0b93c4
--- /dev/null
+++ b/include/rv/kunit.h
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2026-2029 Red Hat, Inc. Gabriele Monaco <gmonaco@redhat.com>
+ *
+ * Declaration of wrappers to allow mocking core functionality, like current,
+ * and other testing utilities.
+ * Necessary only when mocking may be needed. If the RV KUnit test is
+ * enabled, the wrappers incur an additional function call overhead.
+ */
+
+#ifndef _RV_KUNIT_H
+#define _RV_KUNIT_H
+
+#if IS_ENABLED(CONFIG_RV_MONITORS_KUNIT_TEST)
+
+#include <kunit/test.h>
+#include <kunit/test-bug.h>
+#include <linux/delay.h>
+
+int rv_set_testing(struct kunit_suite *suite);
+void rv_clear_testing(struct kunit_suite *suite);
+
+#define RV_KUNIT_MAX_MOCK_TASKS 8
+
+struct rv_kunit_ctx {
+	int reactions, expected;
+	int mock_task_count;
+	struct task_struct *mock_tasks[RV_KUNIT_MAX_MOCK_TASKS];
+};
+
+#define RV_KUNIT_EXPECT_REACTION(test, ctx)                             \
+	do {                                                            \
+		KUNIT_EXPECT_EQ(test, ctx->reactions, ++ctx->expected); \
+		if (ctx->reactions != ctx->expected)                    \
+			ctx->expected = ctx->reactions;                 \
+	} while (0)
+
+#define RV_KUNIT_EXPECT_NO_REACTION(test, ctx)                        \
+	do {                                                          \
+		KUNIT_EXPECT_EQ(test, ctx->reactions, ctx->expected); \
+		if (ctx->reactions != ctx->expected)                  \
+			ctx->expected = ctx->reactions;               \
+	} while (0)
+
+#define RV_KUNIT_EXPECT_REACTION_HERE(test, ctx)                             \
+	for (int __done = ({ RV_KUNIT_EXPECT_NO_REACTION(test, ctx); 0; });  \
+	     !__done;                                                        \
+	     __done = ({ RV_KUNIT_EXPECT_REACTION(test, ctx); 1; }))
+
+struct rv_kunit_mon {
+	struct rv_monitor *rv_this;
+	int (*monitor_init)(void);
+	void (*monitor_destroy)(void);
+	bool is_per_task;
+	int *task_slot;
+	void (*task_reset)(struct task_struct *task);
+};
+
+void prepare_test(struct kunit *test, const struct rv_kunit_mon *mon);
+void teardown_test(void *arg);
+struct task_struct *rv_kunit_alloc_mock_task(struct kunit *test);
+
+void rv_mock_current(struct task_struct *tsk);
+struct task_struct *rv_get_mock_current(void);
+
+#define rv_get_current() (unlikely(kunit_get_current_test()) ? rv_get_mock_current() : current)
+
+#else /* !CONFIG_RV_MONITORS_KUNIT_TEST */
+
+#define rv_get_current() current
+
+#endif /* CONFIG_RV_MONITORS_KUNIT_TEST */
+#endif /* _RV_KUNIT_H */