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, 86 insertions, 0 deletions

diff --git a/drivers/clk/sprd/composite.h b/drivers/clk/sprd/composite.h
new file mode 100644
index 000000000..15cec97d2
--- /dev/null
+++ b/drivers/clk/sprd/composite.h
@@ -0,0 +1,86 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+//
+// Spreadtrum composite clock driver
+//
+// Copyright (C) 2017 Spreadtrum, Inc.
+// Author: Chunyan Zhang <chunyan.zhang@spreadtrum.com>
+
+#ifndef _SPRD_COMPOSITE_H_
+#define _SPRD_COMPOSITE_H_
+
+#include "common.h"
+#include "mux.h"
+#include "div.h"
+
+struct sprd_comp {
+	struct sprd_mux_ssel	mux;
+	struct sprd_div_internal	div;
+	struct sprd_clk_common	common;
+};
+
+#define SPRD_COMP_CLK_HW_INIT_FN(_struct, _name, _parent, _reg, _table,	\
+				 _mshift, _mwidth, _doffset, _dshift,	\
+				 _dwidth, _flags, _fn)			\
+	struct sprd_comp _struct = {					\
+		.mux	= _SPRD_MUX_CLK(_mshift, _mwidth, _table),	\
+		.div	= _SPRD_DIV_CLK(_doffset, _dshift, _dwidth),	\
+		.common = {						\
+			.regmap		= NULL,				\
+			.reg		= _reg,				\
+			.hw.init = _fn(_name, _parent,			\
+				       &sprd_comp_ops, _flags),		\
+		}							\
+	}
+
+#define SPRD_COMP_CLK_TABLE(_struct, _name, _parent, _reg, _table,	\
+			    _mshift, _mwidth, _dshift, _dwidth, _flags)	\
+	SPRD_COMP_CLK_HW_INIT_FN(_struct, _name, _parent, _reg, _table,	\
+				 _mshift, _mwidth, 0x0, _dshift,	\
+				 _dwidth, _flags, CLK_HW_INIT_PARENTS)
+
+#define SPRD_COMP_CLK(_struct, _name, _parent, _reg, _mshift,		\
+		      _mwidth, _dshift, _dwidth, _flags)		\
+	SPRD_COMP_CLK_TABLE(_struct, _name, _parent, _reg, NULL,	\
+			    _mshift, _mwidth, _dshift, _dwidth, _flags)
+
+#define SPRD_COMP_CLK_DATA_TABLE(_struct, _name, _parent, _reg, _table,	\
+				 _mshift, _mwidth, _dshift,		\
+				 _dwidth, _flags)			\
+	SPRD_COMP_CLK_HW_INIT_FN(_struct, _name, _parent, _reg, _table,	\
+				 _mshift, _mwidth, 0x0, _dshift,	\
+				 _dwidth, _flags,			\
+				 CLK_HW_INIT_PARENTS_DATA)
+
+#define SPRD_COMP_CLK_DATA(_struct, _name, _parent, _reg, _mshift,	\
+			   _mwidth, _dshift, _dwidth, _flags)		\
+	SPRD_COMP_CLK_DATA_TABLE(_struct, _name, _parent, _reg, NULL,	\
+				 _mshift, _mwidth, _dshift, _dwidth,	\
+				 _flags)
+
+#define SPRD_COMP_CLK_DATA_TABLE_OFFSET(_struct, _name, _parent, _reg,	\
+					_table, _mshift, _mwidth,	\
+					_doffset, _dshift, _dwidth,	\
+					_flags)				\
+	SPRD_COMP_CLK_HW_INIT_FN(_struct, _name, _parent, _reg, _table,	\
+				 _mshift, _mwidth, _doffset, _dshift,	\
+				 _dwidth, _flags,			\
+				 CLK_HW_INIT_PARENTS_DATA)
+
+#define SPRD_COMP_CLK_DATA_OFFSET(_struct, _name, _parent, _reg,	\
+				  _mshift, _mwidth, _doffset, _dshift,	\
+				  _dwidth, _flags)			\
+	SPRD_COMP_CLK_DATA_TABLE_OFFSET(_struct, _name, _parent, _reg,	\
+					NULL, _mshift, _mwidth,		\
+					_doffset, _dshift, _dwidth,	\
+					_flags)
+
+static inline struct sprd_comp *hw_to_sprd_comp(const struct clk_hw *hw)
+{
+	struct sprd_clk_common *common = hw_to_sprd_clk_common(hw);
+
+	return container_of(common, struct sprd_comp, common);
+}
+
+extern const struct clk_ops sprd_comp_ops;
+
+#endif /* _SPRD_COMPOSITE_H_ */