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, 32 insertions, 0 deletions

diff --git a/drivers/clk/mmp/reset.h b/drivers/clk/mmp/reset.h
new file mode 100644
index 000000000..3d0470ca3
--- /dev/null
+++ b/drivers/clk/mmp/reset.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __MACH_MMP_CLK_RESET_H
+#define __MACH_MMP_CLK_RESET_H
+
+#include <linux/reset-controller.h>
+
+#define MMP_RESET_INVERT	1
+
+struct mmp_clk_reset_cell {
+	unsigned int clk_id;
+	void __iomem *reg;
+	u32 bits;
+	unsigned int flags;
+	spinlock_t *lock;
+};
+
+struct mmp_clk_reset_unit {
+	struct reset_controller_dev rcdev;
+	struct mmp_clk_reset_cell *cells;
+};
+
+#ifdef CONFIG_RESET_CONTROLLER
+void mmp_clk_reset_register(struct device_node *np,
+			struct mmp_clk_reset_cell *cells, int nr_resets);
+#else
+static inline void mmp_clk_reset_register(struct device_node *np,
+			struct mmp_clk_reset_cell *cells, int nr_resets)
+{
+}
+#endif
+
+#endif