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, 56 insertions, 0 deletions

diff --git a/drivers/pinctrl/berlin/berlin.h b/drivers/pinctrl/berlin/berlin.h
new file mode 100644
index 000000000..231aab61d
--- /dev/null
+++ b/drivers/pinctrl/berlin/berlin.h
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Marvell Berlin SoC pinctrl driver.
+ *
+ * Copyright (C) 2014 Marvell Technology Group Ltd.
+ *
+ * Antoine Ténart <antoine.tenart@free-electrons.com>
+ */
+
+#ifndef __PINCTRL_BERLIN_H
+#define __PINCTRL_BERLIN_H
+
+struct berlin_desc_function {
+	const char	*name;
+	u8		muxval;
+};
+
+struct berlin_desc_group {
+	const char			*name;
+	u8				offset;
+	u8				bit_width;
+	u8				lsb;
+	struct berlin_desc_function	*functions;
+};
+
+struct berlin_pinctrl_desc {
+	const struct berlin_desc_group	*groups;
+	unsigned			ngroups;
+};
+
+#define BERLIN_PINCTRL_GROUP(_name, _offset, _width, _lsb, ...)		\
+	{								\
+		.name = _name,						\
+		.offset = _offset,					\
+		.bit_width = _width,					\
+		.lsb = _lsb,						\
+		.functions = (struct berlin_desc_function[]){		\
+			__VA_ARGS__, { } },				\
+	}
+
+#define BERLIN_PINCTRL_FUNCTION(_muxval, _name)		\
+	{						\
+		.name = _name,				\
+		.muxval = _muxval,			\
+	}
+
+#define BERLIN_PINCTRL_FUNCTION_UNKNOWN		{}
+
+int berlin_pinctrl_probe(struct platform_device *pdev,
+			 const struct berlin_pinctrl_desc *desc);
+
+int berlin_pinctrl_probe_regmap(struct platform_device *pdev,
+				const struct berlin_pinctrl_desc *desc,
+				struct regmap *regmap);
+
+#endif /* __PINCTRL_BERLIN_H */