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, 48 insertions, 0 deletions

diff --git a/drivers/clk/tegra/clk-dfll.h b/drivers/clk/tegra/clk-dfll.h
new file mode 100644
index 000000000..fb209eb5f
--- /dev/null
+++ b/drivers/clk/tegra/clk-dfll.h
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * clk-dfll.h - prototypes and macros for the Tegra DFLL clocksource driver
+ * Copyright (C) 2013-2019 NVIDIA Corporation.  All rights reserved.
+ *
+ * Aleksandr Frid <afrid@nvidia.com>
+ * Paul Walmsley <pwalmsley@nvidia.com>
+ */
+
+#ifndef __DRIVERS_CLK_TEGRA_CLK_DFLL_H
+#define __DRIVERS_CLK_TEGRA_CLK_DFLL_H
+
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/types.h>
+
+#include "cvb.h"
+
+/**
+ * struct tegra_dfll_soc_data - SoC-specific hooks/integration for the DFLL driver
+ * @dev: struct device * that holds the OPP table for the DFLL
+ * @max_freq: maximum frequency supported on this SoC
+ * @cvb: CPU frequency table for this SoC
+ * @alignment: parameters of the regulator step and offset
+ * @init_clock_trimmers: callback to initialize clock trimmers
+ * @set_clock_trimmers_high: callback to tune clock trimmers for high voltage
+ * @set_clock_trimmers_low: callback to tune clock trimmers for low voltage
+ */
+struct tegra_dfll_soc_data {
+	struct device *dev;
+	unsigned long max_freq;
+	const struct cvb_table *cvb;
+	struct rail_alignment alignment;
+
+	void (*init_clock_trimmers)(void);
+	void (*set_clock_trimmers_high)(void);
+	void (*set_clock_trimmers_low)(void);
+};
+
+int tegra_dfll_register(struct platform_device *pdev,
+			struct tegra_dfll_soc_data *soc);
+struct tegra_dfll_soc_data *tegra_dfll_unregister(struct platform_device *pdev);
+int tegra_dfll_runtime_suspend(struct device *dev);
+int tegra_dfll_runtime_resume(struct device *dev);
+int tegra_dfll_suspend(struct device *dev);
+int tegra_dfll_resume(struct device *dev);
+
+#endif /* __DRIVERS_CLK_TEGRA_CLK_DFLL_H */