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, 45 insertions, 0 deletions

diff --git a/drivers/pinctrl/bcm/pinctrl-bcm63xx.h b/drivers/pinctrl/bcm/pinctrl-bcm63xx.h
new file mode 100644
index 000000000..3dcfabb94
--- /dev/null
+++ b/drivers/pinctrl/bcm/pinctrl-bcm63xx.h
@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (C) 2021 Álvaro Fernández Rojas <noltari@gmail.com>
+ * Copyright (C) 2016 Jonas Gorski <jonas.gorski@gmail.com>
+ */
+
+#ifndef __PINCTRL_BCM63XX_H__
+#define __PINCTRL_BCM63XX_H__
+
+#include <linux/pinctrl/pinctrl.h>
+
+#define BCM63XX_BANK_GPIOS 32
+
+struct bcm63xx_pinctrl_soc {
+	const struct pinctrl_ops *pctl_ops;
+	const struct pinmux_ops *pmx_ops;
+
+	const struct pinctrl_pin_desc *pins;
+	unsigned npins;
+
+	unsigned int ngpios;
+};
+
+#define BCM_PIN_GROUP(n)	PINCTRL_PINGROUP(#n, n##_pins, ARRAY_SIZE(n##_pins))
+
+struct bcm63xx_pinctrl {
+	struct device *dev;
+	struct regmap *regs;
+
+	struct pinctrl_desc pctl_desc;
+	struct pinctrl_dev *pctl_dev;
+
+	void *driver_data;
+};
+
+static inline unsigned int bcm63xx_bank_pin(unsigned int pin)
+{
+	return pin % BCM63XX_BANK_GPIOS;
+}
+
+int bcm63xx_pinctrl_probe(struct platform_device *pdev,
+			  const struct bcm63xx_pinctrl_soc *soc,
+			  void *driver_data);
+
+#endif /* __PINCTRL_BCM63XX_H__ */