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, 77 insertions, 0 deletions

diff --git a/drivers/clk/actions/owl-gate.c b/drivers/clk/actions/owl-gate.c
new file mode 100644
index 000000000..f11500ba4
--- /dev/null
+++ b/drivers/clk/actions/owl-gate.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0+
+//
+// OWL gate 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/clk-provider.h>
+#include <linux/regmap.h>
+
+#include "owl-gate.h"
+
+void owl_gate_set(const struct owl_clk_common *common,
+		 const struct owl_gate_hw *gate_hw, bool enable)
+{
+	int set = gate_hw->gate_flags & CLK_GATE_SET_TO_DISABLE ? 1 : 0;
+	u32 reg;
+
+	set ^= enable;
+
+	regmap_read(common->regmap, gate_hw->reg, &reg);
+
+	if (set)
+		reg |= BIT(gate_hw->bit_idx);
+	else
+		reg &= ~BIT(gate_hw->bit_idx);
+
+	regmap_write(common->regmap, gate_hw->reg, reg);
+}
+
+static void owl_gate_disable(struct clk_hw *hw)
+{
+	struct owl_gate *gate = hw_to_owl_gate(hw);
+	struct owl_clk_common *common = &gate->common;
+
+	owl_gate_set(common, &gate->gate_hw, false);
+}
+
+static int owl_gate_enable(struct clk_hw *hw)
+{
+	struct owl_gate *gate = hw_to_owl_gate(hw);
+	struct owl_clk_common *common = &gate->common;
+
+	owl_gate_set(common, &gate->gate_hw, true);
+
+	return 0;
+}
+
+int owl_gate_clk_is_enabled(const struct owl_clk_common *common,
+		   const struct owl_gate_hw *gate_hw)
+{
+	u32 reg;
+
+	regmap_read(common->regmap, gate_hw->reg, &reg);
+
+	if (gate_hw->gate_flags & CLK_GATE_SET_TO_DISABLE)
+		reg ^= BIT(gate_hw->bit_idx);
+
+	return !!(reg & BIT(gate_hw->bit_idx));
+}
+
+static int owl_gate_is_enabled(struct clk_hw *hw)
+{
+	struct owl_gate *gate = hw_to_owl_gate(hw);
+	struct owl_clk_common *common = &gate->common;
+
+	return owl_gate_clk_is_enabled(common, &gate->gate_hw);
+}
+
+const struct clk_ops owl_gate_ops = {
+	.disable	= owl_gate_disable,
+	.enable		= owl_gate_enable,
+	.is_enabled	= owl_gate_is_enabled,
+};