selftests/bpf: Reject graph kptr use after RCU unlockgrafted

Add a sleepable verifier test that loads a graph-node local kptr in an
explicit RCU read-side critical section, then passes its node to
bpf_rbtree_remove() after the section ends.

Before the verifier fix, the stale NON_OWN_REF flag makes the node look like
a live borrowed reference and the program is accepted. After the fix, the
pointer is demoted without NON_OWN_REF and the graph kfunc argument is
rejected.

Also exercise a graph kptr loaded while a spin lock provides implicit RCU
protection. The pointer must be invalidated when the lock is released, which
guards the required ordering between non-owning-reference invalidation and
RCU demotion.

Update the existing fault-protected load test state description. The
post-unlock pointer no longer carries NON_OWN_REF, but remains readable
because the load is rewritten to use BPF_PROBE_MEM.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 116 insertions, 0 deletions

diff --git a/tools/perf/util/tool.h b/tools/perf/util/tool.h
new file mode 100644
index 000000000..2a4f124ff
--- /dev/null
+++ b/tools/perf/util/tool.h
@@ -0,0 +1,116 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __PERF_TOOL_H
+#define __PERF_TOOL_H
+
+#include <stdbool.h>
+
+#include <linux/types.h>
+
+struct perf_session;
+union perf_event;
+struct evlist;
+struct perf_sample;
+struct perf_tool;
+struct machine;
+struct ordered_events;
+
+typedef int (*event_sample)(const struct perf_tool *tool, union perf_event *event,
+			    struct perf_sample *sample,
+			    struct machine *machine);
+
+typedef int (*event_op)(const struct perf_tool *tool, union perf_event *event,
+			struct perf_sample *sample, struct machine *machine);
+
+typedef int (*event_attr_op)(const struct perf_tool *tool,
+			     union perf_event *event,
+			     struct evlist **pevlist);
+
+typedef int (*event_op2)(const struct perf_tool *tool, struct perf_session *session,
+			 union perf_event *event);
+typedef s64 (*event_op3)(const struct perf_tool *tool, struct perf_session *session,
+			 union perf_event *event);
+typedef int (*event_op4)(const struct perf_tool *tool, struct perf_session *session,
+			 union perf_event *event, u64 data, const char *str);
+
+typedef int (*event_oe)(const struct perf_tool *tool, union perf_event *event,
+			struct ordered_events *oe);
+
+enum show_feature_header {
+	SHOW_FEAT_NO_HEADER = 0,
+	SHOW_FEAT_HEADER,
+	SHOW_FEAT_HEADER_FULL_INFO,
+};
+
+struct perf_tool {
+	event_sample	sample,
+			read,
+			callchain_deferred;
+	event_op	mmap,
+			mmap2,
+			comm,
+			namespaces,
+			cgroup,
+			fork,
+			exit,
+			lost,
+			lost_samples,
+			aux,
+			itrace_start,
+			aux_output_hw_id,
+			context_switch,
+			throttle,
+			unthrottle,
+			ksymbol,
+			bpf,
+			text_poke;
+
+	event_attr_op	attr;
+	event_attr_op	event_update;
+	event_op2	tracing_data;
+	event_oe	finished_round;
+	event_op2	build_id,
+			id_index,
+			auxtrace_info,
+			auxtrace_error,
+			time_conv,
+			thread_map,
+			cpu_map,
+			stat_config,
+			stat,
+			stat_round,
+			feature,
+			finished_init,
+			bpf_metadata,
+			schedstat_cpu,
+			schedstat_domain;
+	event_op4	compressed;
+	event_op3	auxtrace;
+	bool		ordered_events;
+	bool		ordering_requires_timestamps;
+	bool		namespace_events;
+	bool		cgroup_events;
+	bool		no_warn;
+	bool		dont_split_sample_group;
+	bool		merge_deferred_callchains;
+	enum show_feature_header show_feat_hdr;
+};
+
+void perf_tool__init(struct perf_tool *tool, bool ordered_events);
+
+bool perf_tool__compressed_is_stub(const struct perf_tool *tool);
+
+int process_event_sample_stub(const struct perf_tool *tool,
+			      union perf_event *event,
+			      struct perf_sample *sample,
+			      struct machine *machine);
+
+struct delegate_tool {
+	/** @tool: The actual tool that calls the delegate. */
+	struct perf_tool tool;
+	/** @delegate: The tool that is delegated to. */
+	struct perf_tool *delegate;
+};
+
+void delegate_tool__init(struct delegate_tool *tool, struct perf_tool *delegate);
+
+#endif /* __PERF_TOOL_H */