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, 102 insertions, 0 deletions

diff --git a/drivers/clk/davinci/psc.h b/drivers/clk/davinci/psc.h
new file mode 100644
index 000000000..742672843
--- /dev/null
+++ b/drivers/clk/davinci/psc.h
@@ -0,0 +1,102 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Clock driver for TI Davinci PSC controllers
+ *
+ * Copyright (C) 2018 David Lechner <david@lechnology.com>
+ */
+
+#ifndef __CLK_DAVINCI_PSC_H__
+#define __CLK_DAVINCI_PSC_H__
+
+#include <linux/clk-provider.h>
+#include <linux/types.h>
+
+/* PSC quirk flags */
+#define LPSC_ALWAYS_ENABLED	BIT(0) /* never disable this clock */
+#define LPSC_SET_RATE_PARENT	BIT(1) /* propagate set_rate to parent clock */
+#define LPSC_FORCE		BIT(2) /* requires MDCTL FORCE bit */
+#define LPSC_LOCAL_RESET	BIT(3) /* acts as reset provider */
+
+struct davinci_lpsc_clkdev_info {
+	const char *con_id;
+	const char *dev_id;
+};
+
+#define LPSC_CLKDEV(c, d) {	\
+	.con_id = (c),		\
+	.dev_id = (d)		\
+}
+
+#define LPSC_CLKDEV1(n, c, d) \
+static const struct davinci_lpsc_clkdev_info n[] __initconst = {	\
+	LPSC_CLKDEV((c), (d)),						\
+	{ }								\
+}
+
+#define LPSC_CLKDEV2(n, c1, d1, c2, d2) \
+static const struct davinci_lpsc_clkdev_info n[] __initconst = {	\
+	LPSC_CLKDEV((c1), (d1)),					\
+	LPSC_CLKDEV((c2), (d2)),					\
+	{ }								\
+}
+
+#define LPSC_CLKDEV3(n, c1, d1, c2, d2, c3, d3) \
+static const struct davinci_lpsc_clkdev_info n[] __initconst = {	\
+	LPSC_CLKDEV((c1), (d1)),					\
+	LPSC_CLKDEV((c2), (d2)),					\
+	LPSC_CLKDEV((c3), (d3)),					\
+	{ }								\
+}
+
+/**
+ * davinci_lpsc_clk_info - LPSC module-specific clock information
+ * @name: the clock name
+ * @parent: the parent clock name
+ * @cdevs: optional array of clkdev lookup table info
+ * @md: the local module domain (LPSC id)
+ * @pd: the power domain id
+ * @flags: bitmask of LPSC_* flags
+ */
+struct davinci_lpsc_clk_info {
+	const char *name;
+	const char *parent;
+	const struct davinci_lpsc_clkdev_info *cdevs;
+	u32 md;
+	u32 pd;
+	unsigned long flags;
+};
+
+#define LPSC(m, d, n, p, c, f)	\
+{				\
+	.name	= #n,		\
+	.parent	= #p,		\
+	.cdevs	= (c),		\
+	.md	= (m),		\
+	.pd	= (d),		\
+	.flags	= (f),		\
+}
+
+int davinci_psc_register_clocks(struct device *dev,
+				const struct davinci_lpsc_clk_info *info,
+				u8 num_clks,
+				void __iomem *base);
+
+int of_davinci_psc_clk_init(struct device *dev,
+			    const struct davinci_lpsc_clk_info *info,
+			    u8 num_clks,
+			    void __iomem *base);
+
+/* Device-specific data */
+
+struct davinci_psc_init_data {
+	struct clk_bulk_data *parent_clks;
+	int num_parent_clks;
+	int (*psc_init)(struct device *dev, void __iomem *base);
+};
+
+extern const struct davinci_psc_init_data da850_psc0_init_data;
+extern const struct davinci_psc_init_data da850_psc1_init_data;
+extern const struct davinci_psc_init_data of_da850_psc0_init_data;
+extern const struct davinci_psc_init_data of_da850_psc1_init_data;
+
+#endif /* __CLK_DAVINCI_PSC_H__ */