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, 127 insertions, 0 deletions

diff --git a/drivers/pinctrl/mediatek/mtk-eint.h b/drivers/pinctrl/mediatek/mtk-eint.h
new file mode 100644
index 000000000..3cdd6f631
--- /dev/null
+++ b/drivers/pinctrl/mediatek/mtk-eint.h
@@ -0,0 +1,127 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2014-2025 MediaTek Inc.
+ *
+ * Author: Maoguang Meng <maoguang.meng@mediatek.com>
+ *	   Sean Wang <sean.wang@mediatek.com>
+ *	   Hao Chang <ot_chhao.chang@mediatek.com>
+ *	   Qingliang Li <qingliang.li@mediatek.com>
+ */
+#ifndef __MTK_EINT_H
+#define __MTK_EINT_H
+
+#include <linux/irqdomain.h>
+
+struct mtk_eint_regs {
+	unsigned int	stat;
+	unsigned int	ack;
+	unsigned int	mask;
+	unsigned int	mask_set;
+	unsigned int	mask_clr;
+	unsigned int	sens;
+	unsigned int	sens_set;
+	unsigned int	sens_clr;
+	unsigned int	soft;
+	unsigned int	soft_set;
+	unsigned int	soft_clr;
+	unsigned int	pol;
+	unsigned int	pol_set;
+	unsigned int	pol_clr;
+	unsigned int	dom_en;
+	unsigned int	dbnc_ctrl;
+	unsigned int	dbnc_set;
+	unsigned int	dbnc_clr;
+};
+
+struct mtk_eint_hw {
+	u8		port_mask;
+	u8		ports;
+	unsigned int	ap_num;
+	unsigned int	db_cnt;
+	const unsigned int *db_time;
+};
+
+struct mtk_eint_pin {
+	u16 number;
+	u8 instance;
+	u8 index;
+	bool debounce;
+	bool dual_edge;
+};
+
+extern const unsigned int debounce_time_mt2701[];
+extern const unsigned int debounce_time_mt6765[];
+extern const unsigned int debounce_time_mt6795[];
+extern const unsigned int debounce_time_mt6878[];
+
+struct mtk_eint;
+
+struct mtk_eint_xt {
+	int (*get_gpio_n)(void *data, unsigned long eint_n,
+			  unsigned int *gpio_n,
+			  struct gpio_chip **gpio_chip);
+	int (*get_gpio_state)(void *data, unsigned long eint_n);
+	int (*set_gpio_as_eint)(void *data, unsigned long eint_n);
+};
+
+struct mtk_eint {
+	struct device *dev;
+	void __iomem **base;
+	int nbase;
+	u16 *base_pin_num;
+	struct irq_domain *domain;
+	int irq;
+
+	int *dual_edge;
+	u16 **pin_list;
+	u32 **wake_mask;
+	u32 **cur_mask;
+
+	/* Used to fit into various EINT device */
+	const struct mtk_eint_hw *hw;
+	const struct mtk_eint_regs *regs;
+	struct mtk_eint_pin *pins;
+	u16 num_db_time;
+
+	/* Used to fit into various pinctrl device */
+	void *pctl;
+	const struct mtk_eint_xt *gpio_xlate;
+};
+
+#if IS_ENABLED(CONFIG_EINT_MTK)
+int mtk_eint_do_init(struct mtk_eint *eint, struct mtk_eint_pin *eint_pin);
+int mtk_eint_do_suspend(struct mtk_eint *eint);
+int mtk_eint_do_resume(struct mtk_eint *eint);
+int mtk_eint_set_debounce(struct mtk_eint *eint, unsigned long eint_n,
+			  unsigned int debounce);
+int mtk_eint_find_irq(struct mtk_eint *eint, unsigned long eint_n);
+
+#else
+static inline int mtk_eint_do_init(struct mtk_eint *eint,
+				   struct mtk_eint_pin *eint_pin)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int mtk_eint_do_suspend(struct mtk_eint *eint)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int mtk_eint_do_resume(struct mtk_eint *eint)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int mtk_eint_set_debounce(struct mtk_eint *eint, unsigned long eint_n,
+			  unsigned int debounce)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int mtk_eint_find_irq(struct mtk_eint *eint, unsigned long eint_n)
+{
+	return -EOPNOTSUPP;
+}
+#endif
+#endif /* __MTK_EINT_H */