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, 181 insertions, 0 deletions

diff --git a/drivers/pinctrl/pinmux.h b/drivers/pinctrl/pinmux.h
new file mode 100644
index 000000000..4e826c1a5
--- /dev/null
+++ b/drivers/pinctrl/pinmux.h
@@ -0,0 +1,181 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Internal interface between the core pin control system and the
+ * pinmux portions
+ *
+ * Copyright (C) 2011 ST-Ericsson SA
+ * Written on behalf of Linaro for ST-Ericsson
+ * Based on bits of regulator core, gpio core and clk core
+ *
+ * Author: Linus Walleij <linus.walleij@linaro.org>
+ */
+
+#include <linux/types.h>
+
+struct dentry;
+struct seq_file;
+
+struct pinctrl_dev;
+struct pinctrl_gpio_range;
+struct pinctrl_map;
+struct pinctrl_setting;
+
+#ifdef CONFIG_PINMUX
+
+int pinmux_check_ops(struct pinctrl_dev *pctldev);
+
+int pinmux_validate_map(const struct pinctrl_map *map, int i);
+
+bool pinmux_can_be_used_for_gpio(struct pinctrl_dev *pctldev, unsigned int pin);
+
+int pinmux_request_gpio(struct pinctrl_dev *pctldev,
+			struct pinctrl_gpio_range *range,
+			unsigned int pin, unsigned int gpio);
+void pinmux_free_gpio(struct pinctrl_dev *pctldev, unsigned int pin,
+		      struct pinctrl_gpio_range *range);
+int pinmux_gpio_direction(struct pinctrl_dev *pctldev,
+			  struct pinctrl_gpio_range *range,
+			  unsigned int pin, bool input);
+
+int pinmux_map_to_setting(const struct pinctrl_map *map,
+			  struct pinctrl_setting *setting);
+void pinmux_free_setting(const struct pinctrl_setting *setting);
+int pinmux_enable_setting(const struct pinctrl_setting *setting);
+void pinmux_disable_setting(const struct pinctrl_setting *setting);
+
+#else
+
+static inline int pinmux_check_ops(struct pinctrl_dev *pctldev)
+{
+	return 0;
+}
+
+static inline int pinmux_validate_map(const struct pinctrl_map *map, int i)
+{
+	return 0;
+}
+
+static inline bool pinmux_can_be_used_for_gpio(struct pinctrl_dev *pctldev,
+					       unsigned int pin)
+{
+	return true;
+}
+
+static inline int pinmux_request_gpio(struct pinctrl_dev *pctldev,
+			struct pinctrl_gpio_range *range,
+			unsigned int pin, unsigned int gpio)
+{
+	return 0;
+}
+
+static inline void pinmux_free_gpio(struct pinctrl_dev *pctldev,
+				    unsigned int pin,
+				    struct pinctrl_gpio_range *range)
+{
+}
+
+static inline int pinmux_gpio_direction(struct pinctrl_dev *pctldev,
+					struct pinctrl_gpio_range *range,
+					unsigned int pin, bool input)
+{
+	return 0;
+}
+
+static inline int pinmux_map_to_setting(const struct pinctrl_map *map,
+			  struct pinctrl_setting *setting)
+{
+	return 0;
+}
+
+static inline void pinmux_free_setting(const struct pinctrl_setting *setting)
+{
+}
+
+static inline int pinmux_enable_setting(const struct pinctrl_setting *setting)
+{
+	return 0;
+}
+
+static inline void pinmux_disable_setting(const struct pinctrl_setting *setting)
+{
+}
+
+#endif
+
+#if defined(CONFIG_PINMUX) && defined(CONFIG_DEBUG_FS)
+
+void pinmux_show_map(struct seq_file *s, const struct pinctrl_map *map);
+void pinmux_show_setting(struct seq_file *s,
+			 const struct pinctrl_setting *setting);
+void pinmux_init_device_debugfs(struct dentry *devroot,
+				struct pinctrl_dev *pctldev);
+
+#else
+
+static inline void pinmux_show_map(struct seq_file *s,
+				   const struct pinctrl_map *map)
+{
+}
+
+static inline void pinmux_show_setting(struct seq_file *s,
+				       const struct pinctrl_setting *setting)
+{
+}
+
+static inline void pinmux_init_device_debugfs(struct dentry *devroot,
+					      struct pinctrl_dev *pctldev)
+{
+}
+
+#endif
+
+#ifdef CONFIG_GENERIC_PINMUX_FUNCTIONS
+
+/**
+ * struct function_desc - generic function descriptor
+ * @func: generic data of the pin function (name and groups of pins)
+ * @data: pin controller driver specific data
+ */
+struct function_desc {
+	const struct pinfunction *func;
+	void *data;
+};
+
+int pinmux_generic_get_function_count(struct pinctrl_dev *pctldev);
+
+const char *
+pinmux_generic_get_function_name(struct pinctrl_dev *pctldev,
+				 unsigned int selector);
+
+int pinmux_generic_get_function_groups(struct pinctrl_dev *pctldev,
+				       unsigned int selector,
+				       const char * const **groups,
+				       unsigned int * const ngroups);
+
+const struct function_desc *
+pinmux_generic_get_function(struct pinctrl_dev *pctldev, unsigned int selector);
+
+int pinmux_generic_add_function(struct pinctrl_dev *pctldev,
+				const char *name,
+				const char * const *groups,
+				unsigned int const ngroups,
+				void *data);
+
+int pinmux_generic_add_pinfunction(struct pinctrl_dev *pctldev,
+				   const struct pinfunction *func, void *data);
+
+int pinmux_generic_remove_function(struct pinctrl_dev *pctldev,
+				   unsigned int selector);
+
+void pinmux_generic_free_functions(struct pinctrl_dev *pctldev);
+
+bool pinmux_generic_function_is_gpio(struct pinctrl_dev *pctldev,
+				     unsigned int selector);
+
+#else
+
+static inline void pinmux_generic_free_functions(struct pinctrl_dev *pctldev)
+{
+}
+
+#endif /* CONFIG_GENERIC_PINMUX_FUNCTIONS */