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, 250 insertions, 0 deletions

diff --git a/drivers/clk/clk-bulk.c b/drivers/clk/clk-bulk.c
new file mode 100644
index 000000000..acd9dff30
--- /dev/null
+++ b/drivers/clk/clk-bulk.c
@@ -0,0 +1,250 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2017 NXP
+ *
+ * Dong Aisheng <aisheng.dong@nxp.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/device.h>
+#include <linux/export.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+
+static int __must_check of_clk_bulk_get(struct device *dev,
+					struct device_node *np, int num_clks,
+					struct clk_bulk_data *clks)
+{
+	int ret;
+	int i;
+
+	for (i = 0; i < num_clks; i++) {
+		clks[i].id = NULL;
+		clks[i].clk = NULL;
+	}
+
+	for (i = 0; i < num_clks; i++) {
+		of_property_read_string_index(np, "clock-names", i, &clks[i].id);
+		clks[i].clk = of_clk_get(np, i);
+		if (IS_ERR(clks[i].clk)) {
+			ret = PTR_ERR(clks[i].clk);
+			dev_err_probe(dev, ret, "%pOF: Failed to get clk index: %d (%s)\n",
+				      np, i, clks[i].id);
+			clks[i].clk = NULL;
+			goto err;
+		}
+	}
+
+	return 0;
+
+err:
+	clk_bulk_put(i, clks);
+
+	return ret;
+}
+
+static int __must_check of_clk_bulk_get_all(struct device *dev,
+					    struct device_node *np,
+					    struct clk_bulk_data **clks)
+{
+	struct clk_bulk_data *clk_bulk;
+	int num_clks;
+	int ret;
+
+	num_clks = of_clk_get_parent_count(np);
+	if (!num_clks)
+		return 0;
+
+	clk_bulk = kmalloc_objs(*clk_bulk, num_clks);
+	if (!clk_bulk)
+		return -ENOMEM;
+
+	ret = of_clk_bulk_get(dev, np, num_clks, clk_bulk);
+	if (ret) {
+		kfree(clk_bulk);
+		return ret;
+	}
+
+	*clks = clk_bulk;
+
+	return num_clks;
+}
+
+void clk_bulk_put(int num_clks, struct clk_bulk_data *clks)
+{
+	while (--num_clks >= 0) {
+		clk_put(clks[num_clks].clk);
+		clks[num_clks].clk = NULL;
+	}
+}
+EXPORT_SYMBOL_GPL(clk_bulk_put);
+
+static int __clk_bulk_get(struct device *dev, int num_clks,
+			  struct clk_bulk_data *clks, bool optional)
+{
+	int ret;
+	int i;
+
+	for (i = 0; i < num_clks; i++)
+		clks[i].clk = NULL;
+
+	for (i = 0; i < num_clks; i++) {
+		clks[i].clk = clk_get(dev, clks[i].id);
+		if (IS_ERR(clks[i].clk)) {
+			ret = PTR_ERR(clks[i].clk);
+			clks[i].clk = NULL;
+
+			if (ret == -ENOENT && optional)
+				continue;
+
+			dev_err_probe(dev, ret,
+				      "Failed to get clk '%s'\n",
+				      clks[i].id);
+			goto err;
+		}
+	}
+
+	return 0;
+
+err:
+	clk_bulk_put(i, clks);
+
+	return ret;
+}
+
+int __must_check clk_bulk_get(struct device *dev, int num_clks,
+			      struct clk_bulk_data *clks)
+{
+	return __clk_bulk_get(dev, num_clks, clks, false);
+}
+EXPORT_SYMBOL(clk_bulk_get);
+
+int __must_check clk_bulk_get_optional(struct device *dev, int num_clks,
+				       struct clk_bulk_data *clks)
+{
+	return __clk_bulk_get(dev, num_clks, clks, true);
+}
+EXPORT_SYMBOL_GPL(clk_bulk_get_optional);
+
+void clk_bulk_put_all(int num_clks, struct clk_bulk_data *clks)
+{
+	if (IS_ERR_OR_NULL(clks))
+		return;
+
+	clk_bulk_put(num_clks, clks);
+
+	kfree(clks);
+}
+EXPORT_SYMBOL(clk_bulk_put_all);
+
+int __must_check clk_bulk_get_all(struct device *dev,
+				  struct clk_bulk_data **clks)
+{
+	struct device_node *np = dev_of_node(dev);
+
+	if (!np)
+		return 0;
+
+	return of_clk_bulk_get_all(dev, np, clks);
+}
+EXPORT_SYMBOL(clk_bulk_get_all);
+
+#ifdef CONFIG_HAVE_CLK_PREPARE
+
+/**
+ * clk_bulk_unprepare - undo preparation of a set of clock sources
+ * @num_clks: the number of clk_bulk_data
+ * @clks: the clk_bulk_data table being unprepared
+ *
+ * clk_bulk_unprepare may sleep, which differentiates it from clk_bulk_disable.
+ * Returns 0 on success, -EERROR otherwise.
+ */
+void clk_bulk_unprepare(int num_clks, const struct clk_bulk_data *clks)
+{
+	while (--num_clks >= 0)
+		clk_unprepare(clks[num_clks].clk);
+}
+EXPORT_SYMBOL_GPL(clk_bulk_unprepare);
+
+/**
+ * clk_bulk_prepare - prepare a set of clocks
+ * @num_clks: the number of clk_bulk_data
+ * @clks: the clk_bulk_data table being prepared
+ *
+ * clk_bulk_prepare may sleep, which differentiates it from clk_bulk_enable.
+ * Returns 0 on success, -EERROR otherwise.
+ */
+int __must_check clk_bulk_prepare(int num_clks,
+				  const struct clk_bulk_data *clks)
+{
+	int ret;
+	int i;
+
+	for (i = 0; i < num_clks; i++) {
+		ret = clk_prepare(clks[i].clk);
+		if (ret) {
+			pr_err("Failed to prepare clk '%s': %d\n",
+				clks[i].id, ret);
+			goto err;
+		}
+	}
+
+	return 0;
+
+err:
+	clk_bulk_unprepare(i, clks);
+
+	return  ret;
+}
+EXPORT_SYMBOL_GPL(clk_bulk_prepare);
+
+#endif /* CONFIG_HAVE_CLK_PREPARE */
+
+/**
+ * clk_bulk_disable - gate a set of clocks
+ * @num_clks: the number of clk_bulk_data
+ * @clks: the clk_bulk_data table being gated
+ *
+ * clk_bulk_disable must not sleep, which differentiates it from
+ * clk_bulk_unprepare. clk_bulk_disable must be called before
+ * clk_bulk_unprepare.
+ */
+void clk_bulk_disable(int num_clks, const struct clk_bulk_data *clks)
+{
+
+	while (--num_clks >= 0)
+		clk_disable(clks[num_clks].clk);
+}
+EXPORT_SYMBOL_GPL(clk_bulk_disable);
+
+/**
+ * clk_bulk_enable - ungate a set of clocks
+ * @num_clks: the number of clk_bulk_data
+ * @clks: the clk_bulk_data table being ungated
+ *
+ * clk_bulk_enable must not sleep
+ * Returns 0 on success, -EERROR otherwise.
+ */
+int __must_check clk_bulk_enable(int num_clks, const struct clk_bulk_data *clks)
+{
+	int ret;
+	int i;
+
+	for (i = 0; i < num_clks; i++) {
+		ret = clk_enable(clks[i].clk);
+		if (ret) {
+			pr_err("Failed to enable clk '%s': %d\n",
+				clks[i].id, ret);
+			goto err;
+		}
+	}
+
+	return 0;
+
+err:
+	clk_bulk_disable(i, clks);
+
+	return  ret;
+}
+EXPORT_SYMBOL_GPL(clk_bulk_enable);