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, 17 insertions, 0 deletions

diff --git a/drivers/clk/bcm/clk-hr2.c b/drivers/clk/bcm/clk-hr2.c
new file mode 100644
index 000000000..9f6318f37
--- /dev/null
+++ b/drivers/clk/bcm/clk-hr2.c
@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (C) 2017 Broadcom
+
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/clk-provider.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+
+#include "clk-iproc.h"
+
+static void __init hr2_armpll_init(struct device_node *node)
+{
+	iproc_armpll_setup(node);
+}
+CLK_OF_DECLARE(hr2_armpll, "brcm,hr2-armpll", hr2_armpll_init);