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, 30 insertions, 0 deletions

diff --git a/tools/testing/radix-tree/Makefile b/tools/testing/radix-tree/Makefile
new file mode 100644
index 000000000..b2a6660bb
--- /dev/null
+++ b/tools/testing/radix-tree/Makefile
@@ -0,0 +1,30 @@
+# SPDX-License-Identifier: GPL-2.0
+
+.PHONY: clean
+
+TARGETS = main idr-test multiorder xarray maple
+CORE_OFILES = $(SHARED_OFILES) xarray.o maple.o test.o
+OFILES = main.o $(CORE_OFILES) regression1.o regression2.o \
+	 regression3.o regression4.o tag_check.o multiorder.o idr-test.o \
+	iteration_check.o iteration_check_2.o benchmark.o
+
+targets: generated/map-shift.h generated/bit-length.h $(TARGETS)
+
+include ../shared/shared.mk
+
+main:	$(OFILES)
+
+xarray.o: ../../../lib/test_xarray.c
+idr-test.o: ../../../lib/test_ida.c
+idr-test: idr-test.o $(CORE_OFILES)
+
+xarray: $(CORE_OFILES) xarray.o
+
+maple: $(CORE_OFILES) maple.o
+
+multiorder: multiorder.o $(CORE_OFILES)
+
+clean:
+	$(RM) $(TARGETS) *.o radix-tree.c idr.c generated/*
+
+$(OFILES): $(SHARED_DEPS) *.h