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, 259 insertions, 0 deletions

diff --git a/drivers/clk/clk-conf.c b/drivers/clk/clk-conf.c
new file mode 100644
index 000000000..550b8ae37
--- /dev/null
+++ b/drivers/clk/clk-conf.c
@@ -0,0 +1,259 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2014 Samsung Electronics Co., Ltd.
+ * Sylwester Nawrocki <s.nawrocki@samsung.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/clk/clk-conf.h>
+#include <linux/device.h>
+#include <linux/of.h>
+#include <linux/printk.h>
+#include <linux/slab.h>
+
+static int __set_clk_parents(struct device_node *node, bool clk_supplier)
+{
+	struct of_phandle_args clkspec;
+	int index, rc, num_parents;
+	struct clk *clk, *pclk;
+
+	num_parents = of_count_phandle_with_args(node, "assigned-clock-parents",
+						 "#clock-cells");
+	if (num_parents == -EINVAL)
+		pr_err("clk: invalid value of clock-parents property at %pOF\n",
+		       node);
+
+	for (index = 0; index < num_parents; index++) {
+		rc = of_parse_phandle_with_args(node, "assigned-clock-parents",
+					"#clock-cells",	index, &clkspec);
+		if (rc < 0) {
+			/* skip empty (null) phandles */
+			if (rc == -ENOENT)
+				continue;
+			else
+				return rc;
+		}
+		if (clkspec.np == node && !clk_supplier) {
+			of_node_put(clkspec.np);
+			return 0;
+		}
+		pclk = of_clk_get_from_provider(&clkspec);
+		of_node_put(clkspec.np);
+		if (IS_ERR(pclk)) {
+			if (PTR_ERR(pclk) != -EPROBE_DEFER)
+				pr_warn("clk: couldn't get parent clock %d for %pOF\n",
+					index, node);
+			return PTR_ERR(pclk);
+		}
+
+		rc = of_parse_phandle_with_args(node, "assigned-clocks",
+					"#clock-cells", index, &clkspec);
+		if (rc < 0)
+			goto err;
+		if (clkspec.np == node && !clk_supplier) {
+			of_node_put(clkspec.np);
+			rc = 0;
+			goto err;
+		}
+		clk = of_clk_get_from_provider(&clkspec);
+		of_node_put(clkspec.np);
+		if (IS_ERR(clk)) {
+			if (PTR_ERR(clk) != -EPROBE_DEFER)
+				pr_warn("clk: couldn't get assigned clock %d for %pOF\n",
+					index, node);
+			rc = PTR_ERR(clk);
+			goto err;
+		}
+
+		rc = clk_set_parent(clk, pclk);
+		if (rc < 0)
+			pr_err("clk: failed to reparent %s to %s: %d\n",
+			       __clk_get_name(clk), __clk_get_name(pclk), rc);
+		clk_put(clk);
+		clk_put(pclk);
+	}
+	return 0;
+err:
+	clk_put(pclk);
+	return rc;
+}
+
+static int __set_clk_rates(struct device_node *node, bool clk_supplier)
+{
+	struct of_phandle_args clkspec;
+	int rc, count, count_64, index;
+	struct clk *clk;
+	u64 *rates_64 __free(kfree) = NULL;
+	u32 *rates __free(kfree) = NULL;
+
+	count = of_property_count_u32_elems(node, "assigned-clock-rates");
+	count_64 = of_property_count_u64_elems(node, "assigned-clock-rates-u64");
+	if (count_64 > 0) {
+		count = count_64;
+		rates_64 = kcalloc(count, sizeof(*rates_64), GFP_KERNEL);
+		if (!rates_64)
+			return -ENOMEM;
+
+		rc = of_property_read_u64_array(node,
+						"assigned-clock-rates-u64",
+						rates_64, count);
+	} else if (count > 0) {
+		rates = kcalloc(count, sizeof(*rates), GFP_KERNEL);
+		if (!rates)
+			return -ENOMEM;
+
+		rc = of_property_read_u32_array(node, "assigned-clock-rates",
+						rates, count);
+	} else {
+		return 0;
+	}
+
+	if (rc)
+		return rc;
+
+	for (index = 0; index < count; index++) {
+		unsigned long rate;
+
+		if (rates_64)
+			rate = rates_64[index];
+		else
+			rate = rates[index];
+
+		if (rate) {
+			rc = of_parse_phandle_with_args(node, "assigned-clocks",
+					"#clock-cells",	index, &clkspec);
+			if (rc < 0) {
+				/* skip empty (null) phandles */
+				if (rc == -ENOENT)
+					continue;
+				else
+					return rc;
+			}
+			if (clkspec.np == node && !clk_supplier) {
+				of_node_put(clkspec.np);
+				return 0;
+			}
+
+			clk = of_clk_get_from_provider(&clkspec);
+			of_node_put(clkspec.np);
+			if (IS_ERR(clk)) {
+				if (PTR_ERR(clk) != -EPROBE_DEFER)
+					pr_warn("clk: couldn't get clock %d for %pOF\n",
+						index, node);
+				return PTR_ERR(clk);
+			}
+
+			rc = clk_set_rate(clk, rate);
+			if (rc < 0)
+				pr_err("clk: couldn't set %s clk rate to %lu (%d), current rate: %lu\n",
+				       __clk_get_name(clk), rate, rc,
+				       clk_get_rate(clk));
+			clk_put(clk);
+		}
+	}
+	return 0;
+}
+
+static int __set_clk_spread_spectrum(struct device_node *node, bool clk_supplier)
+{
+	u32 elem_size = sizeof(struct clk_spread_spectrum);
+	struct clk_spread_spectrum *sscs;
+	struct of_phandle_args clkspec;
+	int rc, count, index;
+	struct clk *clk;
+
+	/* modfreq, spreadPercent, modmethod */
+	count = of_property_count_elems_of_size(node, "assigned-clock-sscs", elem_size);
+	if (count <= 0)
+		return 0;
+
+	sscs = kcalloc(count, elem_size, GFP_KERNEL);
+	if (!sscs)
+		return -ENOMEM;
+
+	rc = of_property_read_u32_array(node, "assigned-clock-sscs", (u32 *)sscs,
+					count * 3);
+	if (rc)
+		goto free_sscs;
+
+	for (index = 0; index < count; index++) {
+		struct clk_spread_spectrum *conf = &sscs[index];
+		struct clk_hw *hw;
+
+		if (!conf->modfreq_hz && !conf->spread_bp && !conf->method)
+			continue;
+
+		rc = of_parse_phandle_with_args(node, "assigned-clocks", "#clock-cells",
+						index, &clkspec);
+		if (rc < 0) {
+			/* skip empty (null) phandles */
+			if (rc == -ENOENT) {
+				rc = 0;
+				continue;
+			} else
+				goto free_sscs;
+		}
+
+		if (clkspec.np == node && !clk_supplier) {
+			of_node_put(clkspec.np);
+			goto free_sscs;
+		}
+
+		clk = of_clk_get_from_provider(&clkspec);
+		of_node_put(clkspec.np);
+		if (IS_ERR(clk)) {
+			if (PTR_ERR(clk) != -EPROBE_DEFER)
+				pr_warn("clk: couldn't get clock %d for %pOF\n",
+					index, node);
+			rc = PTR_ERR(clk);
+			goto free_sscs;
+		}
+
+		hw = __clk_get_hw(clk);
+		rc = clk_hw_set_spread_spectrum(hw, conf);
+		if (rc < 0) {
+			pr_err("clk: couldn't set %s clk spread spectrum %u %u %u: %d\n",
+			       __clk_get_name(clk), conf->modfreq_hz, conf->spread_bp,
+			       conf->method, rc);
+			/* Do not fail */
+			rc = 0;
+		}
+		clk_put(clk);
+	}
+
+free_sscs:
+	kfree(sscs);
+	return rc;
+}
+
+/**
+ * of_clk_set_defaults() - parse and set assigned clocks configuration
+ * @node: device node to apply clock settings for
+ * @clk_supplier: true if clocks supplied by @node should also be considered
+ *
+ * This function parses 'assigned-{clocks/clock-parents/clock-rates}' properties
+ * and sets any specified clock parents and rates. The @clk_supplier argument
+ * should be set to true if @node may be also a clock supplier of any clock
+ * listed in its 'assigned-clocks' or 'assigned-clock-parents' properties.
+ * If @clk_supplier is false the function exits returning 0 as soon as it
+ * determines the @node is also a supplier of any of the clocks.
+ */
+int of_clk_set_defaults(struct device_node *node, bool clk_supplier)
+{
+	int rc;
+
+	if (!node)
+		return 0;
+
+	rc = __set_clk_spread_spectrum(node, clk_supplier);
+	if (rc < 0)
+		return rc;
+
+	rc = __set_clk_parents(node, clk_supplier);
+	if (rc < 0)
+		return rc;
+
+	return __set_clk_rates(node, clk_supplier);
+}
+EXPORT_SYMBOL_GPL(of_clk_set_defaults);