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, 465 insertions, 0 deletions

diff --git a/drivers/clk/clk-composite.c b/drivers/clk/clk-composite.c
new file mode 100644
index 000000000..11842bce5
--- /dev/null
+++ b/drivers/clk/clk-composite.c
@@ -0,0 +1,465 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2013 NVIDIA CORPORATION.  All rights reserved.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+
+static u8 clk_composite_get_parent(struct clk_hw *hw)
+{
+	struct clk_composite *composite = to_clk_composite(hw);
+	const struct clk_ops *mux_ops = composite->mux_ops;
+	struct clk_hw *mux_hw = composite->mux_hw;
+
+	__clk_hw_set_clk(mux_hw, hw);
+
+	return mux_ops->get_parent(mux_hw);
+}
+
+static int clk_composite_set_parent(struct clk_hw *hw, u8 index)
+{
+	struct clk_composite *composite = to_clk_composite(hw);
+	const struct clk_ops *mux_ops = composite->mux_ops;
+	struct clk_hw *mux_hw = composite->mux_hw;
+
+	__clk_hw_set_clk(mux_hw, hw);
+
+	return mux_ops->set_parent(mux_hw, index);
+}
+
+static unsigned long clk_composite_recalc_rate(struct clk_hw *hw,
+					    unsigned long parent_rate)
+{
+	struct clk_composite *composite = to_clk_composite(hw);
+	const struct clk_ops *rate_ops = composite->rate_ops;
+	struct clk_hw *rate_hw = composite->rate_hw;
+
+	__clk_hw_set_clk(rate_hw, hw);
+
+	return rate_ops->recalc_rate(rate_hw, parent_rate);
+}
+
+static int clk_composite_determine_rate_for_parent(struct clk_hw *rate_hw,
+						   struct clk_rate_request *req,
+						   struct clk_hw *parent_hw,
+						   const struct clk_ops *rate_ops)
+{
+	req->best_parent_hw = parent_hw;
+	req->best_parent_rate = clk_hw_get_rate(parent_hw);
+
+	return rate_ops->determine_rate(rate_hw, req);
+}
+
+static int clk_composite_determine_rate(struct clk_hw *hw,
+					struct clk_rate_request *req)
+{
+	struct clk_composite *composite = to_clk_composite(hw);
+	const struct clk_ops *rate_ops = composite->rate_ops;
+	const struct clk_ops *mux_ops = composite->mux_ops;
+	struct clk_hw *rate_hw = composite->rate_hw;
+	struct clk_hw *mux_hw = composite->mux_hw;
+	struct clk_hw *parent;
+	unsigned long rate_diff;
+	unsigned long best_rate_diff = ULONG_MAX;
+	unsigned long best_rate = 0;
+	int i, ret;
+
+	if (rate_hw && rate_ops && rate_ops->determine_rate &&
+	    mux_hw && mux_ops && mux_ops->set_parent) {
+		req->best_parent_hw = NULL;
+
+		if (clk_hw_get_flags(hw) & CLK_SET_RATE_NO_REPARENT) {
+			struct clk_rate_request tmp_req;
+
+			parent = clk_hw_get_parent(mux_hw);
+
+			clk_hw_forward_rate_request(hw, req, parent, &tmp_req, req->rate);
+			ret = clk_composite_determine_rate_for_parent(rate_hw,
+								      &tmp_req,
+								      parent,
+								      rate_ops);
+			if (ret)
+				return ret;
+
+			req->rate = tmp_req.rate;
+			req->best_parent_hw = tmp_req.best_parent_hw;
+			req->best_parent_rate = tmp_req.best_parent_rate;
+
+			return 0;
+		}
+
+		for (i = 0; i < clk_hw_get_num_parents(mux_hw); i++) {
+			struct clk_rate_request tmp_req;
+
+			parent = clk_hw_get_parent_by_index(mux_hw, i);
+			if (!parent)
+				continue;
+
+			clk_hw_forward_rate_request(hw, req, parent, &tmp_req, req->rate);
+			ret = clk_composite_determine_rate_for_parent(rate_hw,
+								      &tmp_req,
+								      parent,
+								      rate_ops);
+			if (ret)
+				continue;
+
+			if (req->rate >= tmp_req.rate)
+				rate_diff = req->rate - tmp_req.rate;
+			else
+				rate_diff = tmp_req.rate - req->rate;
+
+			if (!rate_diff || !req->best_parent_hw
+				       || best_rate_diff > rate_diff) {
+				req->best_parent_hw = parent;
+				req->best_parent_rate = tmp_req.best_parent_rate;
+				best_rate_diff = rate_diff;
+				best_rate = tmp_req.rate;
+			}
+
+			if (!rate_diff)
+				return 0;
+		}
+
+		req->rate = best_rate;
+		return 0;
+	} else if (rate_hw && rate_ops && rate_ops->determine_rate) {
+		__clk_hw_set_clk(rate_hw, hw);
+		return rate_ops->determine_rate(rate_hw, req);
+	} else if (mux_hw && mux_ops && mux_ops->determine_rate) {
+		__clk_hw_set_clk(mux_hw, hw);
+		return mux_ops->determine_rate(mux_hw, req);
+	} else {
+		pr_err("clk: clk_composite_determine_rate function called, but no mux or rate callback set!\n");
+		return -EINVAL;
+	}
+}
+
+static int clk_composite_set_rate(struct clk_hw *hw, unsigned long rate,
+			       unsigned long parent_rate)
+{
+	struct clk_composite *composite = to_clk_composite(hw);
+	const struct clk_ops *rate_ops = composite->rate_ops;
+	struct clk_hw *rate_hw = composite->rate_hw;
+
+	__clk_hw_set_clk(rate_hw, hw);
+
+	return rate_ops->set_rate(rate_hw, rate, parent_rate);
+}
+
+static int clk_composite_set_rate_and_parent(struct clk_hw *hw,
+					     unsigned long rate,
+					     unsigned long parent_rate,
+					     u8 index)
+{
+	struct clk_composite *composite = to_clk_composite(hw);
+	const struct clk_ops *rate_ops = composite->rate_ops;
+	const struct clk_ops *mux_ops = composite->mux_ops;
+	struct clk_hw *rate_hw = composite->rate_hw;
+	struct clk_hw *mux_hw = composite->mux_hw;
+	unsigned long temp_rate;
+
+	__clk_hw_set_clk(rate_hw, hw);
+	__clk_hw_set_clk(mux_hw, hw);
+
+	temp_rate = rate_ops->recalc_rate(rate_hw, parent_rate);
+	if (temp_rate > rate) {
+		rate_ops->set_rate(rate_hw, rate, parent_rate);
+		mux_ops->set_parent(mux_hw, index);
+	} else {
+		mux_ops->set_parent(mux_hw, index);
+		rate_ops->set_rate(rate_hw, rate, parent_rate);
+	}
+
+	return 0;
+}
+
+static int clk_composite_is_enabled(struct clk_hw *hw)
+{
+	struct clk_composite *composite = to_clk_composite(hw);
+	const struct clk_ops *gate_ops = composite->gate_ops;
+	struct clk_hw *gate_hw = composite->gate_hw;
+
+	__clk_hw_set_clk(gate_hw, hw);
+
+	return gate_ops->is_enabled(gate_hw);
+}
+
+static int clk_composite_enable(struct clk_hw *hw)
+{
+	struct clk_composite *composite = to_clk_composite(hw);
+	const struct clk_ops *gate_ops = composite->gate_ops;
+	struct clk_hw *gate_hw = composite->gate_hw;
+
+	__clk_hw_set_clk(gate_hw, hw);
+
+	return gate_ops->enable(gate_hw);
+}
+
+static void clk_composite_disable(struct clk_hw *hw)
+{
+	struct clk_composite *composite = to_clk_composite(hw);
+	const struct clk_ops *gate_ops = composite->gate_ops;
+	struct clk_hw *gate_hw = composite->gate_hw;
+
+	__clk_hw_set_clk(gate_hw, hw);
+
+	gate_ops->disable(gate_hw);
+}
+
+static struct clk_hw *__clk_hw_register_composite(struct device *dev,
+			const char *name, const char * const *parent_names,
+			const struct clk_parent_data *pdata, int num_parents,
+			struct clk_hw *mux_hw, const struct clk_ops *mux_ops,
+			struct clk_hw *rate_hw, const struct clk_ops *rate_ops,
+			struct clk_hw *gate_hw, const struct clk_ops *gate_ops,
+			unsigned long flags)
+{
+	struct clk_hw *hw;
+	struct clk_init_data init = {};
+	struct clk_composite *composite;
+	struct clk_ops *clk_composite_ops;
+	int ret;
+
+	composite = kzalloc_obj(*composite);
+	if (!composite)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = name;
+	init.flags = flags;
+	if (parent_names)
+		init.parent_names = parent_names;
+	else
+		init.parent_data = pdata;
+	init.num_parents = num_parents;
+	hw = &composite->hw;
+
+	clk_composite_ops = &composite->ops;
+
+	if (mux_hw && mux_ops) {
+		if (!mux_ops->get_parent) {
+			hw = ERR_PTR(-EINVAL);
+			goto err;
+		}
+
+		composite->mux_hw = mux_hw;
+		composite->mux_ops = mux_ops;
+		clk_composite_ops->get_parent = clk_composite_get_parent;
+		if (mux_ops->set_parent)
+			clk_composite_ops->set_parent = clk_composite_set_parent;
+		if (mux_ops->determine_rate)
+			clk_composite_ops->determine_rate = clk_composite_determine_rate;
+	}
+
+	if (rate_hw && rate_ops) {
+		if (!rate_ops->recalc_rate) {
+			hw = ERR_PTR(-EINVAL);
+			goto err;
+		}
+		clk_composite_ops->recalc_rate = clk_composite_recalc_rate;
+
+		if (rate_ops->determine_rate)
+			clk_composite_ops->determine_rate =
+				clk_composite_determine_rate;
+
+		/* .set_rate requires .determine_rate */
+		if (rate_ops->set_rate) {
+			if (rate_ops->determine_rate)
+				clk_composite_ops->set_rate =
+						clk_composite_set_rate;
+			else
+				WARN(1, "%s: missing determine_rate op is required\n",
+						__func__);
+		}
+
+		composite->rate_hw = rate_hw;
+		composite->rate_ops = rate_ops;
+	}
+
+	if (mux_hw && mux_ops && rate_hw && rate_ops) {
+		if (mux_ops->set_parent && rate_ops->set_rate)
+			clk_composite_ops->set_rate_and_parent =
+			clk_composite_set_rate_and_parent;
+	}
+
+	if (gate_hw && gate_ops) {
+		if (!gate_ops->is_enabled || !gate_ops->enable ||
+		    !gate_ops->disable) {
+			hw = ERR_PTR(-EINVAL);
+			goto err;
+		}
+
+		composite->gate_hw = gate_hw;
+		composite->gate_ops = gate_ops;
+		clk_composite_ops->is_enabled = clk_composite_is_enabled;
+		clk_composite_ops->enable = clk_composite_enable;
+		clk_composite_ops->disable = clk_composite_disable;
+	}
+
+	init.ops = clk_composite_ops;
+	composite->hw.init = &init;
+
+	ret = clk_hw_register(dev, hw);
+	if (ret) {
+		hw = ERR_PTR(ret);
+		goto err;
+	}
+
+	if (composite->mux_hw)
+		composite->mux_hw->clk = hw->clk;
+
+	if (composite->rate_hw)
+		composite->rate_hw->clk = hw->clk;
+
+	if (composite->gate_hw)
+		composite->gate_hw->clk = hw->clk;
+
+	return hw;
+
+err:
+	kfree(composite);
+	return hw;
+}
+
+struct clk_hw *clk_hw_register_composite(struct device *dev, const char *name,
+			const char * const *parent_names, int num_parents,
+			struct clk_hw *mux_hw, const struct clk_ops *mux_ops,
+			struct clk_hw *rate_hw, const struct clk_ops *rate_ops,
+			struct clk_hw *gate_hw, const struct clk_ops *gate_ops,
+			unsigned long flags)
+{
+	return __clk_hw_register_composite(dev, name, parent_names, NULL,
+					   num_parents, mux_hw, mux_ops,
+					   rate_hw, rate_ops, gate_hw,
+					   gate_ops, flags);
+}
+EXPORT_SYMBOL_GPL(clk_hw_register_composite);
+
+struct clk_hw *clk_hw_register_composite_pdata(struct device *dev,
+			const char *name,
+			const struct clk_parent_data *parent_data,
+			int num_parents,
+			struct clk_hw *mux_hw, const struct clk_ops *mux_ops,
+			struct clk_hw *rate_hw, const struct clk_ops *rate_ops,
+			struct clk_hw *gate_hw, const struct clk_ops *gate_ops,
+			unsigned long flags)
+{
+	return __clk_hw_register_composite(dev, name, NULL, parent_data,
+					   num_parents, mux_hw, mux_ops,
+					   rate_hw, rate_ops, gate_hw,
+					   gate_ops, flags);
+}
+
+struct clk *clk_register_composite(struct device *dev, const char *name,
+			const char * const *parent_names, int num_parents,
+			struct clk_hw *mux_hw, const struct clk_ops *mux_ops,
+			struct clk_hw *rate_hw, const struct clk_ops *rate_ops,
+			struct clk_hw *gate_hw, const struct clk_ops *gate_ops,
+			unsigned long flags)
+{
+	struct clk_hw *hw;
+
+	hw = clk_hw_register_composite(dev, name, parent_names, num_parents,
+			mux_hw, mux_ops, rate_hw, rate_ops, gate_hw, gate_ops,
+			flags);
+	if (IS_ERR(hw))
+		return ERR_CAST(hw);
+	return hw->clk;
+}
+EXPORT_SYMBOL_GPL(clk_register_composite);
+
+struct clk *clk_register_composite_pdata(struct device *dev, const char *name,
+			const struct clk_parent_data *parent_data,
+			int num_parents,
+			struct clk_hw *mux_hw, const struct clk_ops *mux_ops,
+			struct clk_hw *rate_hw, const struct clk_ops *rate_ops,
+			struct clk_hw *gate_hw, const struct clk_ops *gate_ops,
+			unsigned long flags)
+{
+	struct clk_hw *hw;
+
+	hw = clk_hw_register_composite_pdata(dev, name, parent_data,
+			num_parents, mux_hw, mux_ops, rate_hw, rate_ops,
+			gate_hw, gate_ops, flags);
+	if (IS_ERR(hw))
+		return ERR_CAST(hw);
+	return hw->clk;
+}
+
+void clk_unregister_composite(struct clk *clk)
+{
+	struct clk_composite *composite;
+	struct clk_hw *hw;
+
+	hw = __clk_get_hw(clk);
+	if (!hw)
+		return;
+
+	composite = to_clk_composite(hw);
+
+	clk_unregister(clk);
+	kfree(composite);
+}
+
+void clk_hw_unregister_composite(struct clk_hw *hw)
+{
+	struct clk_composite *composite;
+
+	composite = to_clk_composite(hw);
+
+	clk_hw_unregister(hw);
+	kfree(composite);
+}
+EXPORT_SYMBOL_GPL(clk_hw_unregister_composite);
+
+static void devm_clk_hw_release_composite(struct device *dev, void *res)
+{
+	clk_hw_unregister_composite(*(struct clk_hw **)res);
+}
+
+static struct clk_hw *__devm_clk_hw_register_composite(struct device *dev,
+			const char *name, const char * const *parent_names,
+			const struct clk_parent_data *pdata, int num_parents,
+			struct clk_hw *mux_hw, const struct clk_ops *mux_ops,
+			struct clk_hw *rate_hw, const struct clk_ops *rate_ops,
+			struct clk_hw *gate_hw, const struct clk_ops *gate_ops,
+			unsigned long flags)
+{
+	struct clk_hw **ptr, *hw;
+
+	ptr = devres_alloc(devm_clk_hw_release_composite, sizeof(*ptr),
+			   GFP_KERNEL);
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+
+	hw = __clk_hw_register_composite(dev, name, parent_names, pdata,
+					 num_parents, mux_hw, mux_ops, rate_hw,
+					 rate_ops, gate_hw, gate_ops, flags);
+
+	if (!IS_ERR(hw)) {
+		*ptr = hw;
+		devres_add(dev, ptr);
+	} else {
+		devres_free(ptr);
+	}
+
+	return hw;
+}
+
+struct clk_hw *devm_clk_hw_register_composite_pdata(struct device *dev,
+			const char *name,
+			const struct clk_parent_data *parent_data,
+			int num_parents,
+			struct clk_hw *mux_hw, const struct clk_ops *mux_ops,
+			struct clk_hw *rate_hw, const struct clk_ops *rate_ops,
+			struct clk_hw *gate_hw, const struct clk_ops *gate_ops,
+			unsigned long flags)
+{
+	return __devm_clk_hw_register_composite(dev, name, NULL, parent_data,
+						num_parents, mux_hw, mux_ops,
+						rate_hw, rate_ops, gate_hw,
+						gate_ops, flags);
+}
+EXPORT_SYMBOL_GPL(devm_clk_hw_register_composite_pdata);