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, 30 insertions, 0 deletions

diff --git a/lib/kunit/debugfs.h b/lib/kunit/debugfs.h
new file mode 100644
index 000000000..dcc7d7556
--- /dev/null
+++ b/lib/kunit/debugfs.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020, Oracle and/or its affiliates.
+ */
+
+#ifndef _KUNIT_DEBUGFS_H
+#define _KUNIT_DEBUGFS_H
+
+#include <kunit/test.h>
+
+#ifdef CONFIG_KUNIT_DEBUGFS
+
+void kunit_debugfs_create_suite(struct kunit_suite *suite);
+void kunit_debugfs_destroy_suite(struct kunit_suite *suite);
+void kunit_debugfs_init(void);
+void kunit_debugfs_cleanup(void);
+
+#else
+
+static inline void kunit_debugfs_create_suite(struct kunit_suite *suite) { }
+
+static inline void kunit_debugfs_destroy_suite(struct kunit_suite *suite) { }
+
+static inline void kunit_debugfs_init(void) { }
+
+static inline void kunit_debugfs_cleanup(void) { }
+
+#endif /* CONFIG_KUNIT_DEBUGFS */
+
+#endif /* _KUNIT_DEBUGFS_H */