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, 86 insertions, 0 deletions

diff --git a/drivers/clk/actions/owl-common.c b/drivers/clk/actions/owl-common.c
new file mode 100644
index 000000000..b3dded204
--- /dev/null
+++ b/drivers/clk/actions/owl-common.c
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0+
+//
+// OWL common clock driver
+//
+// Copyright (c) 2014 Actions Semi Inc.
+// Author: David Liu <liuwei@actions-semi.com>
+//
+// Copyright (c) 2018 Linaro Ltd.
+// Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#include "owl-common.h"
+
+static const struct regmap_config owl_regmap_config = {
+	.reg_bits	= 32,
+	.reg_stride	= 4,
+	.val_bits	= 32,
+	.max_register	= 0x00cc,
+};
+
+static void owl_clk_set_regmap(const struct owl_clk_desc *desc,
+			 struct regmap *regmap)
+{
+	int i;
+	struct owl_clk_common *clks;
+
+	for (i = 0; i < desc->num_clks; i++) {
+		clks = desc->clks[i];
+		if (!clks)
+			continue;
+
+		clks->regmap = regmap;
+	}
+}
+
+int owl_clk_regmap_init(struct platform_device *pdev,
+			struct owl_clk_desc *desc)
+{
+	void __iomem *base;
+	struct regmap *regmap;
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	regmap = devm_regmap_init_mmio(&pdev->dev, base, &owl_regmap_config);
+	if (IS_ERR(regmap)) {
+		pr_err("failed to init regmap\n");
+		return PTR_ERR(regmap);
+	}
+
+	owl_clk_set_regmap(desc, regmap);
+	desc->regmap = regmap;
+
+	return 0;
+}
+
+int owl_clk_probe(struct device *dev, struct clk_hw_onecell_data *hw_clks)
+{
+	int i, ret;
+	struct clk_hw *hw;
+
+	for (i = 0; i < hw_clks->num; i++) {
+		const char *name;
+
+		hw = hw_clks->hws[i];
+		if (IS_ERR_OR_NULL(hw))
+			continue;
+
+		name = hw->init->name;
+		ret = devm_clk_hw_register(dev, hw);
+		if (ret) {
+			dev_err(dev, "Couldn't register clock %d - %s\n",
+				i, name);
+			return ret;
+		}
+	}
+
+	ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get, hw_clks);
+	if (ret)
+		dev_err(dev, "Failed to add clock provider\n");
+
+	return ret;
+}