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, 172 insertions, 0 deletions

diff --git a/drivers/clk/ti/clockdomain.c b/drivers/clk/ti/clockdomain.c
new file mode 100644
index 000000000..c897ad7e6
--- /dev/null
+++ b/drivers/clk/ti/clockdomain.c
@@ -0,0 +1,172 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * OMAP clockdomain support
+ *
+ * Copyright (C) 2013 Texas Instruments, Inc.
+ *
+ * Tero Kristo <t-kristo@ti.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/clk/ti.h>
+
+#include "clock.h"
+
+#undef pr_fmt
+#define pr_fmt(fmt) "%s: " fmt, __func__
+
+/**
+ * omap2_clkops_enable_clkdm - increment usecount on clkdm of @hw
+ * @hw: struct clk_hw * of the clock being enabled
+ *
+ * Increment the usecount of the clockdomain of the clock pointed to
+ * by @hw; if the usecount is 1, the clockdomain will be "enabled."
+ * Only needed for clocks that don't use omap2_dflt_clk_enable() as
+ * their enable function pointer.  Passes along the return value of
+ * clkdm_clk_enable(), -EINVAL if @hw is not associated with a
+ * clockdomain, or 0 if clock framework-based clockdomain control is
+ * not implemented.
+ */
+int omap2_clkops_enable_clkdm(struct clk_hw *hw)
+{
+	struct clk_hw_omap *clk;
+	int ret = 0;
+
+	clk = to_clk_hw_omap(hw);
+
+	if (unlikely(!clk->clkdm)) {
+		pr_err("%s: %s: no clkdm set ?!\n", __func__,
+		       clk_hw_get_name(hw));
+		return -EINVAL;
+	}
+
+	if (ti_clk_get_features()->flags & TI_CLK_DISABLE_CLKDM_CONTROL) {
+		pr_err("%s: %s: clkfw-based clockdomain control disabled ?!\n",
+		       __func__, clk_hw_get_name(hw));
+		return 0;
+	}
+
+	ret = ti_clk_ll_ops->clkdm_clk_enable(clk->clkdm, hw->clk);
+	WARN(ret, "%s: could not enable %s's clockdomain %s: %d\n",
+	     __func__, clk_hw_get_name(hw), clk->clkdm_name, ret);
+
+	return ret;
+}
+
+/**
+ * omap2_clkops_disable_clkdm - decrement usecount on clkdm of @hw
+ * @hw: struct clk_hw * of the clock being disabled
+ *
+ * Decrement the usecount of the clockdomain of the clock pointed to
+ * by @hw; if the usecount is 0, the clockdomain will be "disabled."
+ * Only needed for clocks that don't use omap2_dflt_clk_disable() as their
+ * disable function pointer.  No return value.
+ */
+void omap2_clkops_disable_clkdm(struct clk_hw *hw)
+{
+	struct clk_hw_omap *clk;
+
+	clk = to_clk_hw_omap(hw);
+
+	if (unlikely(!clk->clkdm)) {
+		pr_err("%s: %s: no clkdm set ?!\n", __func__,
+		       clk_hw_get_name(hw));
+		return;
+	}
+
+	if (ti_clk_get_features()->flags & TI_CLK_DISABLE_CLKDM_CONTROL) {
+		pr_err("%s: %s: clkfw-based clockdomain control disabled ?!\n",
+		       __func__, clk_hw_get_name(hw));
+		return;
+	}
+
+	ti_clk_ll_ops->clkdm_clk_disable(clk->clkdm, hw->clk);
+}
+
+/**
+ * omap2_init_clk_clkdm - look up a clockdomain name, store pointer in clk
+ * @hw: Pointer to clk_hw_omap used to obtain OMAP clock struct ptr to use
+ *
+ * Convert a clockdomain name stored in a struct clk 'clk' into a
+ * clockdomain pointer, and save it into the struct clk.  Intended to be
+ * called during clk_register(). Returns 0 on success, -EERROR otherwise.
+ */
+int omap2_init_clk_clkdm(struct clk_hw *hw)
+{
+	struct clk_hw_omap *clk = to_clk_hw_omap(hw);
+	struct clockdomain *clkdm;
+	const char *clk_name;
+
+	if (!clk->clkdm_name)
+		return 0;
+
+	clk_name = __clk_get_name(hw->clk);
+
+	clkdm = ti_clk_ll_ops->clkdm_lookup(clk->clkdm_name);
+	if (clkdm) {
+		pr_debug("clock: associated clk %s to clkdm %s\n",
+			 clk_name, clk->clkdm_name);
+		clk->clkdm = clkdm;
+	} else {
+		pr_debug("clock: could not associate clk %s to clkdm %s\n",
+			 clk_name, clk->clkdm_name);
+	}
+
+	return 0;
+}
+
+static void __init of_ti_clockdomain_setup(struct device_node *node)
+{
+	struct clk *clk;
+	struct clk_hw *clk_hw;
+	const char *clkdm_name = ti_dt_clk_name(node);
+	int i;
+	unsigned int num_clks;
+
+	num_clks = of_clk_get_parent_count(node);
+
+	for (i = 0; i < num_clks; i++) {
+		clk = of_clk_get(node, i);
+		if (IS_ERR(clk)) {
+			pr_err("%s: Failed get %pOF' clock nr %d (%ld)\n",
+			       __func__, node, i, PTR_ERR(clk));
+			continue;
+		}
+		clk_hw = __clk_get_hw(clk);
+		if (!omap2_clk_is_hw_omap(clk_hw)) {
+			pr_warn("can't setup clkdm for basic clk %s\n",
+				__clk_get_name(clk));
+			clk_put(clk);
+			continue;
+		}
+		to_clk_hw_omap(clk_hw)->clkdm_name = clkdm_name;
+		omap2_init_clk_clkdm(clk_hw);
+		clk_put(clk);
+	}
+}
+
+static const struct of_device_id ti_clkdm_match_table[] __initconst = {
+	{ .compatible = "ti,clockdomain" },
+	{ }
+};
+
+/**
+ * ti_dt_clockdomains_setup - setup device tree clockdomains
+ *
+ * Initializes clockdomain nodes for a SoC. This parses through all the
+ * nodes with compatible = "ti,clockdomain", and add the clockdomain
+ * info for all the clocks listed under these. This function shall be
+ * called after rest of the DT clock init has completed and all
+ * clock nodes have been registered.
+ */
+void __init ti_dt_clockdomains_setup(void)
+{
+	struct device_node *np;
+	for_each_matching_node(np, ti_clkdm_match_table) {
+		of_ti_clockdomain_setup(np);
+	}
+}