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, 192 insertions, 0 deletions

diff --git a/drivers/clk/mmp/clk.c b/drivers/clk/mmp/clk.c
new file mode 100644
index 000000000..48b746bef
--- /dev/null
+++ b/drivers/clk/mmp/clk.c
@@ -0,0 +1,192 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/io.h>
+#include <linux/clk-provider.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+
+#include "clk.h"
+
+void mmp_clk_init(struct device_node *np, struct mmp_clk_unit *unit,
+		int nr_clks)
+{
+	struct clk **clk_table;
+
+	clk_table = kzalloc_objs(struct clk *, nr_clks);
+	if (!clk_table)
+		return;
+
+	unit->clk_table = clk_table;
+	unit->nr_clks = nr_clks;
+	unit->clk_data.clks = clk_table;
+	unit->clk_data.clk_num = nr_clks;
+	of_clk_add_provider(np, of_clk_src_onecell_get, &unit->clk_data);
+}
+
+void mmp_register_fixed_rate_clks(struct mmp_clk_unit *unit,
+				struct mmp_param_fixed_rate_clk *clks,
+				int size)
+{
+	int i;
+	struct clk *clk;
+
+	for (i = 0; i < size; i++) {
+		clk = clk_register_fixed_rate(NULL, clks[i].name,
+					clks[i].parent_name,
+					clks[i].flags,
+					clks[i].fixed_rate);
+		if (IS_ERR(clk)) {
+			pr_err("%s: failed to register clock %s\n",
+			       __func__, clks[i].name);
+			continue;
+		}
+		if (clks[i].id)
+			unit->clk_table[clks[i].id] = clk;
+	}
+}
+
+void mmp_register_fixed_factor_clks(struct mmp_clk_unit *unit,
+				struct mmp_param_fixed_factor_clk *clks,
+				int size)
+{
+	struct clk *clk;
+	int i;
+
+	for (i = 0; i < size; i++) {
+		clk = clk_register_fixed_factor(NULL, clks[i].name,
+						clks[i].parent_name,
+						clks[i].flags, clks[i].mult,
+						clks[i].div);
+		if (IS_ERR(clk)) {
+			pr_err("%s: failed to register clock %s\n",
+			       __func__, clks[i].name);
+			continue;
+		}
+		if (clks[i].id)
+			unit->clk_table[clks[i].id] = clk;
+	}
+}
+
+void mmp_register_general_gate_clks(struct mmp_clk_unit *unit,
+				struct mmp_param_general_gate_clk *clks,
+				void __iomem *base, int size)
+{
+	struct clk *clk;
+	int i;
+
+	for (i = 0; i < size; i++) {
+		clk = clk_register_gate(NULL, clks[i].name,
+					clks[i].parent_name,
+					clks[i].flags,
+					base + clks[i].offset,
+					clks[i].bit_idx,
+					clks[i].gate_flags,
+					clks[i].lock);
+
+		if (IS_ERR(clk)) {
+			pr_err("%s: failed to register clock %s\n",
+			       __func__, clks[i].name);
+			continue;
+		}
+		if (clks[i].id)
+			unit->clk_table[clks[i].id] = clk;
+	}
+}
+
+void mmp_register_gate_clks(struct mmp_clk_unit *unit,
+			struct mmp_param_gate_clk *clks,
+			void __iomem *base, int size)
+{
+	struct clk *clk;
+	int i;
+
+	for (i = 0; i < size; i++) {
+		clk = mmp_clk_register_gate(NULL, clks[i].name,
+					clks[i].parent_name,
+					clks[i].flags,
+					base + clks[i].offset,
+					clks[i].mask,
+					clks[i].val_enable,
+					clks[i].val_disable,
+					clks[i].gate_flags,
+					clks[i].lock);
+
+		if (IS_ERR(clk)) {
+			pr_err("%s: failed to register clock %s\n",
+			       __func__, clks[i].name);
+			continue;
+		}
+		if (clks[i].id)
+			unit->clk_table[clks[i].id] = clk;
+	}
+}
+
+void mmp_register_mux_clks(struct mmp_clk_unit *unit,
+			struct mmp_param_mux_clk *clks,
+			void __iomem *base, int size)
+{
+	struct clk *clk;
+	int i;
+
+	for (i = 0; i < size; i++) {
+		clk = clk_register_mux(NULL, clks[i].name,
+					clks[i].parent_name,
+					clks[i].num_parents,
+					clks[i].flags,
+					base + clks[i].offset,
+					clks[i].shift,
+					clks[i].width,
+					clks[i].mux_flags,
+					clks[i].lock);
+
+		if (IS_ERR(clk)) {
+			pr_err("%s: failed to register clock %s\n",
+			       __func__, clks[i].name);
+			continue;
+		}
+		if (clks[i].id)
+			unit->clk_table[clks[i].id] = clk;
+	}
+}
+
+void mmp_register_div_clks(struct mmp_clk_unit *unit,
+			struct mmp_param_div_clk *clks,
+			void __iomem *base, int size)
+{
+	struct clk *clk;
+	int i;
+
+	for (i = 0; i < size; i++) {
+		clk = clk_register_divider(NULL, clks[i].name,
+					clks[i].parent_name,
+					clks[i].flags,
+					base + clks[i].offset,
+					clks[i].shift,
+					clks[i].width,
+					clks[i].div_flags,
+					clks[i].lock);
+
+		if (IS_ERR(clk)) {
+			pr_err("%s: failed to register clock %s\n",
+			       __func__, clks[i].name);
+			continue;
+		}
+		if (clks[i].id)
+			unit->clk_table[clks[i].id] = clk;
+	}
+}
+
+void mmp_clk_add(struct mmp_clk_unit *unit, unsigned int id,
+			struct clk *clk)
+{
+	if (IS_ERR_OR_NULL(clk)) {
+		pr_err("CLK %d has invalid pointer %p\n", id, clk);
+		return;
+	}
+	if (id >= unit->nr_clks) {
+		pr_err("CLK %d is invalid\n", id);
+		return;
+	}
+
+	unit->clk_table[id] = clk;
+}