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, 54 insertions, 0 deletions

diff --git a/drivers/pinctrl/devicetree.h b/drivers/pinctrl/devicetree.h
new file mode 100644
index 000000000..def76aba9
--- /dev/null
+++ b/drivers/pinctrl/devicetree.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Internal interface to pinctrl device tree integration
+ *
+ * Copyright (C) 2012 NVIDIA CORPORATION. All rights reserved.
+ */
+
+#include <linux/errno.h>
+
+struct device_node;
+struct of_phandle_args;
+
+struct pinctrl;
+struct pinctrl_dev;
+
+#ifdef CONFIG_OF
+
+void pinctrl_dt_free_maps(struct pinctrl *p);
+int pinctrl_dt_to_map(struct pinctrl *p, struct pinctrl_dev *pctldev);
+
+int pinctrl_count_index_with_args(const struct device_node *np,
+				  const char *list_name);
+
+int pinctrl_parse_index_with_args(const struct device_node *np,
+				  const char *list_name, int index,
+				  struct of_phandle_args *out_args);
+
+#else
+
+static inline int pinctrl_dt_to_map(struct pinctrl *p,
+				    struct pinctrl_dev *pctldev)
+{
+	return 0;
+}
+
+static inline void pinctrl_dt_free_maps(struct pinctrl *p)
+{
+}
+
+static inline int pinctrl_count_index_with_args(const struct device_node *np,
+						const char *list_name)
+{
+	return -ENODEV;
+}
+
+static inline int
+pinctrl_parse_index_with_args(const struct device_node *np,
+			      const char *list_name, int index,
+			      struct of_phandle_args *out_args)
+{
+	return -ENODEV;
+}
+
+#endif