ftrace: Synchronize the initialization of ftrace_opsgrafted

There's some internal state that ftrace_ops needs to have set, but since
it can be declared outside of the ftrace.c code, it calls
ftrace_ops_init() on the ops in every global function. The issue is that
if two tasks call it on the same ops at the same time it is possible to
have the initialization of one corrupt the initialization of the other
call.

Create a ops_mutex to use to synchronize every initialization of the
ftrace_ops. The mutex is taken within checking the ftrace_ops flag that
states it was initializied but the flag is checked again after the mutex
has been taken. Checking first outside the mutex allows it to shortcut
having to take the mutex. But then the check needs to be done again after
the mute is taken in case of races.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home
Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock")
Reported-by: sashiko-bot@kernel.org
Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 222 insertions, 0 deletions

diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h
new file mode 100644
index 000000000..0ae16da06
--- /dev/null
+++ b/drivers/of/of_private.h
@@ -0,0 +1,222 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+#ifndef _LINUX_OF_PRIVATE_H
+#define _LINUX_OF_PRIVATE_H
+/*
+ * Private symbols used by OF support code
+ *
+ * Paul Mackerras	August 1996.
+ * Copyright (C) 1996-2005 Paul Mackerras.
+ */
+
+#define FDT_ALIGN_SIZE 8
+#define MAX_RESERVED_REGIONS    64
+
+/**
+ * struct alias_prop - Alias property in 'aliases' node
+ * @link:	List node to link the structure in aliases_lookup list
+ * @alias:	Alias property name
+ * @np:		Pointer to device_node that the alias stands for
+ * @id:		Index value from end of alias name
+ * @stem:	Alias string without the index
+ *
+ * The structure represents one alias property of 'aliases' node as
+ * an entry in aliases_lookup list.
+ */
+struct alias_prop {
+	struct list_head link;
+	const char *alias;
+	struct device_node *np;
+	int id;
+	char stem[];
+};
+
+#if defined(CONFIG_SPARC)
+#define OF_ROOT_NODE_ADDR_CELLS_DEFAULT 2
+#else
+#define OF_ROOT_NODE_ADDR_CELLS_DEFAULT 1
+#endif
+
+#define OF_ROOT_NODE_SIZE_CELLS_DEFAULT 1
+
+extern struct mutex of_mutex;
+extern raw_spinlock_t devtree_lock;
+extern struct list_head aliases_lookup;
+extern struct kset *of_kset;
+
+struct kunit;
+extern void of_root_kunit_skip(struct kunit *test);
+
+#if defined(CONFIG_OF_DYNAMIC)
+extern int of_property_notify(int action, struct device_node *np,
+			      struct property *prop, struct property *old_prop);
+extern void of_node_release(struct kobject *kobj);
+extern int __of_changeset_apply_entries(struct of_changeset *ocs,
+					int *ret_revert);
+extern int __of_changeset_apply_notify(struct of_changeset *ocs);
+extern int __of_changeset_revert_entries(struct of_changeset *ocs,
+					 int *ret_apply);
+extern int __of_changeset_revert_notify(struct of_changeset *ocs);
+#else /* CONFIG_OF_DYNAMIC */
+static inline int of_property_notify(int action, struct device_node *np,
+				     struct property *prop, struct property *old_prop)
+{
+	return 0;
+}
+#endif /* CONFIG_OF_DYNAMIC */
+
+#if defined(CONFIG_OF_DYNAMIC) && defined(CONFIG_OF_ADDRESS)
+void of_platform_register_reconfig_notifier(void);
+#else
+static inline void of_platform_register_reconfig_notifier(void) { }
+#endif
+
+#if defined(CONFIG_OF_KOBJ)
+int of_node_is_attached(const struct device_node *node);
+int __of_add_property_sysfs(struct device_node *np, struct property *pp);
+void __of_remove_property_sysfs(struct device_node *np, const struct property *prop);
+void __of_update_property_sysfs(struct device_node *np, struct property *newprop,
+		const struct property *oldprop);
+int __of_attach_node_sysfs(struct device_node *np);
+void __of_detach_node_sysfs(struct device_node *np);
+#else
+static inline int __of_add_property_sysfs(struct device_node *np, struct property *pp)
+{
+	return 0;
+}
+static inline void __of_remove_property_sysfs(struct device_node *np, const struct property *prop) {}
+static inline void __of_update_property_sysfs(struct device_node *np,
+		struct property *newprop, const struct property *oldprop) {}
+static inline int __of_attach_node_sysfs(struct device_node *np)
+{
+	return 0;
+}
+static inline void __of_detach_node_sysfs(struct device_node *np) {}
+#endif
+
+#if defined(CONFIG_OF_RESOLVE)
+int of_resolve_phandles(struct device_node *tree);
+#endif
+
+void __of_phandle_cache_inv_entry(phandle handle);
+
+#if defined(CONFIG_OF_OVERLAY)
+void of_overlay_mutex_lock(void);
+void of_overlay_mutex_unlock(void);
+#else
+static inline void of_overlay_mutex_lock(void) {};
+static inline void of_overlay_mutex_unlock(void) {};
+#endif
+
+#if defined(CONFIG_OF_UNITTEST) && defined(CONFIG_OF_OVERLAY)
+extern void __init unittest_unflatten_overlay_base(void);
+#else
+static inline void unittest_unflatten_overlay_base(void) {};
+#endif
+
+extern void *__unflatten_device_tree(const void *blob,
+			      struct device_node *dad,
+			      struct device_node **mynodes,
+			      void *(*dt_alloc)(u64 size, u64 align),
+			      bool detached);
+
+void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align));
+
+/**
+ * General utilities for working with live trees.
+ *
+ * All functions with two leading underscores operate
+ * without taking node references, so you either have to
+ * own the devtree lock or work on detached trees only.
+ */
+struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags);
+void __of_prop_free(struct property *prop);
+struct device_node *__of_node_dup(const struct device_node *np,
+				  const char *full_name);
+
+struct device_node *__of_find_node_by_path(const struct device_node *parent,
+						const char *path);
+struct device_node *__of_find_node_by_full_path(struct device_node *node,
+						const char *path);
+
+extern const void *__of_get_property(const struct device_node *np,
+				     const char *name, int *lenp);
+extern int __of_add_property(struct device_node *np, struct property *prop);
+extern int __of_remove_property(struct device_node *np, struct property *prop);
+extern int __of_update_property(struct device_node *np,
+		struct property *newprop, struct property **oldprop);
+
+extern void __of_detach_node(struct device_node *np);
+
+extern void __of_sysfs_remove_bin_file(struct device_node *np,
+				       const struct property *prop);
+
+/* illegal phandle value (set when unresolved) */
+#define OF_PHANDLE_ILLEGAL	0xdeadbeef
+
+/* iterators for transactions, used for overlays */
+/* forward iterator */
+#define for_each_transaction_entry(_oft, _te) \
+	list_for_each_entry(_te, &(_oft)->te_list, node)
+
+/* reverse iterator */
+#define for_each_transaction_entry_reverse(_oft, _te) \
+	list_for_each_entry_reverse(_te, &(_oft)->te_list, node)
+
+extern int of_bus_n_addr_cells(struct device_node *np);
+extern int of_bus_n_size_cells(struct device_node *np);
+
+const __be32 *of_irq_parse_imap_parent(const __be32 *imap, int len,
+				       struct of_phandle_args *out_irq);
+
+struct bus_dma_region;
+#if defined(CONFIG_OF_ADDRESS) && defined(CONFIG_HAS_DMA)
+int of_dma_get_range(struct device_node *np,
+		const struct bus_dma_region **map);
+struct device_node *__of_get_dma_parent(const struct device_node *np);
+#else
+static inline int of_dma_get_range(struct device_node *np,
+		const struct bus_dma_region **map)
+{
+	return -ENODEV;
+}
+static inline struct device_node *__of_get_dma_parent(const struct device_node *np)
+{
+	return of_get_parent(np);
+}
+#endif
+
+int fdt_scan_reserved_mem(void);
+void __init fdt_scan_reserved_mem_late(void);
+
+bool of_fdt_device_is_available(const void *blob, unsigned long node);
+
+/* Max address size we deal with */
+#define OF_MAX_ADDR_CELLS	4
+#define OF_CHECK_ADDR_COUNT(na)	((na) > 0 && (na) <= OF_MAX_ADDR_CELLS)
+#define OF_CHECK_COUNTS(na, ns)	(OF_CHECK_ADDR_COUNT(na) && (ns) > 0)
+
+/* Debug utility */
+#ifdef DEBUG
+static void __maybe_unused of_dump_addr(const char *s, const __be32 *addr, int na)
+{
+	pr_debug("%s", s);
+	while (na--)
+		pr_cont(" %08x", be32_to_cpu(*(addr++)));
+	pr_cont("\n");
+}
+#else
+static void __maybe_unused of_dump_addr(const char *s, const __be32 *addr, int na) { }
+#endif
+
+static inline bool is_pseudo_property(const char *prop_name)
+{
+	return !of_prop_cmp(prop_name, "name") ||
+		!of_prop_cmp(prop_name, "phandle") ||
+		!of_prop_cmp(prop_name, "linux,phandle");
+}
+
+#if IS_ENABLED(CONFIG_KUNIT)
+int __of_address_resource_bounds(struct resource *r, u64 start, u64 size);
+#endif
+
+#endif /* _LINUX_OF_PRIVATE_H */