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, 23 insertions, 0 deletions

diff --git a/drivers/clk/ux500/reset-prcc.h b/drivers/clk/ux500/reset-prcc.h
new file mode 100644
index 000000000..353c9719f
--- /dev/null
+++ b/drivers/clk/ux500/reset-prcc.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __RESET_PRCC_H
+#define __RESET_PRCC_H
+
+#include <linux/reset-controller.h>
+#include <linux/io.h>
+
+/**
+ * struct u8500_prcc_reset - U8500 PRCC reset controller state
+ * @rcdev: reset controller device
+ * @phy_base: the physical base address for each PRCC block
+ * @base: the remapped PRCC bases
+ */
+struct u8500_prcc_reset {
+	struct reset_controller_dev rcdev;
+	u32 phy_base[CLKRST_MAX];
+	void __iomem *base[CLKRST_MAX];
+};
+
+void u8500_prcc_reset_init(struct device_node *np, struct u8500_prcc_reset *ur);
+
+#endif