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, 35 insertions, 0 deletions

diff --git a/drivers/clk/sunxi/clk-a10-codec.c b/drivers/clk/sunxi/clk-a10-codec.c
new file mode 100644
index 000000000..6fc6de044
--- /dev/null
+++ b/drivers/clk/sunxi/clk-a10-codec.c
@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2013 Emilio López
+ *
+ * Emilio López <emilio@elopez.com.ar>
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+
+#define SUN4I_CODEC_GATE	31
+
+static void __init sun4i_codec_clk_setup(struct device_node *node)
+{
+	struct clk *clk;
+	const char *clk_name = node->name, *parent_name;
+	void __iomem *reg;
+
+	reg = of_io_request_and_map(node, 0, of_node_full_name(node));
+	if (IS_ERR(reg))
+		return;
+
+	of_property_read_string(node, "clock-output-names", &clk_name);
+	parent_name = of_clk_get_parent_name(node, 0);
+
+	clk = clk_register_gate(NULL, clk_name, parent_name,
+				CLK_SET_RATE_PARENT, reg,
+				SUN4I_CODEC_GATE, 0, NULL);
+
+	if (!IS_ERR(clk))
+		of_clk_add_provider(node, of_clk_src_simple_get, clk);
+}
+CLK_OF_DECLARE(sun4i_codec, "allwinner,sun4i-a10-codec-clk",
+	       sun4i_codec_clk_setup);