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, 168 insertions, 0 deletions

diff --git a/drivers/clk/sprd/gate.h b/drivers/clk/sprd/gate.h
new file mode 100644
index 000000000..775519eb1
--- /dev/null
+++ b/drivers/clk/sprd/gate.h
@@ -0,0 +1,168 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+//
+// Spreadtrum gate clock driver
+//
+// Copyright (C) 2017 Spreadtrum, Inc.
+// Author: Chunyan Zhang <chunyan.zhang@spreadtrum.com>
+
+#ifndef _SPRD_GATE_H_
+#define _SPRD_GATE_H_
+
+#include "common.h"
+
+struct sprd_gate {
+	u32			enable_mask;
+	u16			flags;
+	u16			sc_offset;
+	u16			udelay;
+
+	struct sprd_clk_common	common;
+};
+
+/*
+ * sprd_gate->flags is used for:
+ * CLK_GATE_SET_TO_DISABLE	BIT(0)
+ * CLK_GATE_HIWORD_MASK		BIT(1)
+ * CLK_GATE_BIG_ENDIAN		BIT(2)
+ * so we define new flags from	BIT(3)
+ */
+#define SPRD_GATE_NON_AON BIT(3) /* not always powered on, check before read */
+
+#define SPRD_SC_GATE_CLK_HW_INIT_FN(_struct, _name, _parent, _reg,	\
+				    _sc_offset, _enable_mask, _flags,	\
+				    _gate_flags, _udelay, _ops, _fn)	\
+	struct sprd_gate _struct = {					\
+		.enable_mask	= _enable_mask,				\
+		.sc_offset	= _sc_offset,				\
+		.flags		= _gate_flags,				\
+		.udelay		= _udelay,				\
+		.common	= {						\
+			.regmap		= NULL,				\
+			.reg		= _reg,				\
+			.hw.init	= _fn(_name, _parent,		\
+					      _ops, _flags),		\
+		}							\
+	}
+
+#define SPRD_SC_GATE_CLK_OPS_UDELAY(_struct, _name, _parent, _reg,	\
+				    _sc_offset, _enable_mask, _flags,	\
+				    _gate_flags, _udelay, _ops)		\
+	SPRD_SC_GATE_CLK_HW_INIT_FN(_struct, _name, _parent, _reg,	\
+				    _sc_offset, _enable_mask, _flags,	\
+				    _gate_flags, _udelay, _ops, CLK_HW_INIT)
+
+#define SPRD_SC_GATE_CLK_OPS(_struct, _name, _parent, _reg, _sc_offset,	\
+			     _enable_mask, _flags, _gate_flags, _ops)	\
+	SPRD_SC_GATE_CLK_OPS_UDELAY(_struct, _name, _parent, _reg,	\
+				    _sc_offset, _enable_mask, _flags,	\
+				    _gate_flags, 0, _ops)
+
+#define SPRD_SC_GATE_CLK(_struct, _name, _parent, _reg, _sc_offset,	\
+			 _enable_mask, _flags, _gate_flags)		\
+	SPRD_SC_GATE_CLK_OPS(_struct, _name, _parent, _reg, _sc_offset,	\
+			     _enable_mask, _flags, _gate_flags,		\
+			     &sprd_sc_gate_ops)
+
+#define SPRD_GATE_CLK(_struct, _name, _parent, _reg,			\
+		      _enable_mask, _flags, _gate_flags)		\
+	SPRD_SC_GATE_CLK_OPS(_struct, _name, _parent, _reg, 0,		\
+			     _enable_mask, _flags, _gate_flags,		\
+			     &sprd_gate_ops)
+
+#define SPRD_PLL_SC_GATE_CLK(_struct, _name, _parent, _reg, _sc_offset,	\
+			     _enable_mask, _flags, _gate_flags,		\
+			     _udelay)					\
+	SPRD_SC_GATE_CLK_OPS_UDELAY(_struct, _name, _parent, _reg,	\
+				    _sc_offset,	_enable_mask, _flags,	\
+				    _gate_flags, _udelay,		\
+				    &sprd_pll_sc_gate_ops)
+
+
+#define SPRD_SC_GATE_CLK_HW_OPS_UDELAY(_struct, _name, _parent, _reg,	\
+				       _sc_offset, _enable_mask,	\
+				       _flags, _gate_flags,		\
+				       _udelay, _ops)			\
+	SPRD_SC_GATE_CLK_HW_INIT_FN(_struct, _name, _parent, _reg,	\
+				    _sc_offset, _enable_mask, _flags,	\
+				    _gate_flags, _udelay, _ops,		\
+				    CLK_HW_INIT_HW)
+
+#define SPRD_SC_GATE_CLK_HW_OPS(_struct, _name, _parent, _reg,		\
+				_sc_offset, _enable_mask, _flags,	\
+				_gate_flags, _ops)			\
+	SPRD_SC_GATE_CLK_HW_OPS_UDELAY(_struct, _name, _parent, _reg,	\
+				       _sc_offset, _enable_mask,	\
+				       _flags, _gate_flags, 0, _ops)
+
+#define SPRD_SC_GATE_CLK_HW(_struct, _name, _parent, _reg,		\
+			    _sc_offset, _enable_mask, _flags,		\
+			    _gate_flags)				\
+	SPRD_SC_GATE_CLK_HW_OPS(_struct, _name, _parent, _reg,		\
+				_sc_offset, _enable_mask, _flags,	\
+				_gate_flags, &sprd_sc_gate_ops)
+
+#define SPRD_GATE_CLK_HW(_struct, _name, _parent, _reg,			\
+			 _enable_mask, _flags, _gate_flags)		\
+	SPRD_SC_GATE_CLK_HW_OPS(_struct, _name, _parent, _reg, 0,	\
+				_enable_mask, _flags, _gate_flags,	\
+				&sprd_gate_ops)
+
+#define SPRD_PLL_SC_GATE_CLK_HW(_struct, _name, _parent, _reg,		\
+				_sc_offset, _enable_mask, _flags,	\
+				_gate_flags, _udelay)			\
+	SPRD_SC_GATE_CLK_HW_OPS_UDELAY(_struct, _name, _parent, _reg,	\
+				       _sc_offset, _enable_mask,	\
+				       _flags, _gate_flags, _udelay,	\
+				       &sprd_pll_sc_gate_ops)
+
+#define SPRD_SC_GATE_CLK_FW_NAME_OPS_UDELAY(_struct, _name, _parent,	\
+					    _reg, _sc_offset,		\
+					    _enable_mask, _flags,	\
+					    _gate_flags, _udelay, _ops)	\
+	SPRD_SC_GATE_CLK_HW_INIT_FN(_struct, _name, _parent, _reg,	\
+				    _sc_offset, _enable_mask, _flags,	\
+				    _gate_flags, _udelay, _ops,		\
+				    CLK_HW_INIT_FW_NAME)
+
+#define SPRD_SC_GATE_CLK_FW_NAME_OPS(_struct, _name, _parent, _reg,	\
+				     _sc_offset, _enable_mask, _flags,	\
+				     _gate_flags, _ops)			\
+	SPRD_SC_GATE_CLK_FW_NAME_OPS_UDELAY(_struct, _name, _parent,	\
+					    _reg, _sc_offset,		\
+					    _enable_mask, _flags,	\
+					    _gate_flags, 0, _ops)
+
+#define SPRD_SC_GATE_CLK_FW_NAME(_struct, _name, _parent, _reg,		\
+				 _sc_offset, _enable_mask, _flags,	\
+				 _gate_flags)				\
+	SPRD_SC_GATE_CLK_FW_NAME_OPS(_struct, _name, _parent, _reg,	\
+				     _sc_offset, _enable_mask, _flags,	\
+				     _gate_flags, &sprd_sc_gate_ops)
+
+#define SPRD_GATE_CLK_FW_NAME(_struct, _name, _parent, _reg,		\
+			      _enable_mask, _flags, _gate_flags)	\
+	SPRD_SC_GATE_CLK_FW_NAME_OPS(_struct, _name, _parent, _reg, 0,	\
+				     _enable_mask, _flags, _gate_flags,	\
+				     &sprd_gate_ops)
+
+#define SPRD_PLL_SC_GATE_CLK_FW_NAME(_struct, _name, _parent, _reg,	\
+				     _sc_offset, _enable_mask, _flags,	\
+				     _gate_flags, _udelay)		\
+	SPRD_SC_GATE_CLK_FW_NAME_OPS_UDELAY(_struct, _name, _parent,	\
+					    _reg, _sc_offset,		\
+					    _enable_mask, _flags,	\
+					    _gate_flags, _udelay,	\
+					    &sprd_pll_sc_gate_ops)
+
+static inline struct sprd_gate *hw_to_sprd_gate(const struct clk_hw *hw)
+{
+	struct sprd_clk_common *common = hw_to_sprd_clk_common(hw);
+
+	return container_of(common, struct sprd_gate, common);
+}
+
+extern const struct clk_ops sprd_gate_ops;
+extern const struct clk_ops sprd_sc_gate_ops;
+extern const struct clk_ops sprd_pll_sc_gate_ops;
+
+#endif /* _SPRD_GATE_H_ */