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, 135 insertions, 0 deletions

diff --git a/drivers/clk/versatile/clk-impd1.c b/drivers/clk/versatile/clk-impd1.c
new file mode 100644
index 000000000..328dd47f1
--- /dev/null
+++ b/drivers/clk/versatile/clk-impd1.c
@@ -0,0 +1,135 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Clock driver for the ARM Integrator/IM-PD1 board
+ * Copyright (C) 2012-2013 Linus Walleij
+ */
+#include <linux/clk-provider.h>
+#include <linux/clkdev.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
+
+#include "icst.h"
+#include "clk-icst.h"
+
+#define IMPD1_OSC1	0x00
+#define IMPD1_OSC2	0x04
+#define IMPD1_LOCK	0x08
+
+/*
+ * There are two VCO's on the IM-PD1
+ */
+
+static const struct icst_params impd1_vco1_params = {
+	.ref		= 24000000,	/* 24 MHz */
+	.vco_max	= ICST525_VCO_MAX_3V,
+	.vco_min	= ICST525_VCO_MIN,
+	.vd_min		= 12,
+	.vd_max		= 519,
+	.rd_min		= 3,
+	.rd_max		= 120,
+	.s2div		= icst525_s2div,
+	.idx2s		= icst525_idx2s,
+};
+
+static const struct clk_icst_desc impd1_icst1_desc = {
+	.params = &impd1_vco1_params,
+	.vco_offset = IMPD1_OSC1,
+	.lock_offset = IMPD1_LOCK,
+};
+
+static const struct icst_params impd1_vco2_params = {
+	.ref		= 24000000,	/* 24 MHz */
+	.vco_max	= ICST525_VCO_MAX_3V,
+	.vco_min	= ICST525_VCO_MIN,
+	.vd_min		= 12,
+	.vd_max		= 519,
+	.rd_min		= 3,
+	.rd_max		= 120,
+	.s2div		= icst525_s2div,
+	.idx2s		= icst525_idx2s,
+};
+
+static const struct clk_icst_desc impd1_icst2_desc = {
+	.params = &impd1_vco2_params,
+	.vco_offset = IMPD1_OSC2,
+	.lock_offset = IMPD1_LOCK,
+};
+
+static int integrator_impd1_clk_spawn(struct device *dev,
+				      struct device_node *parent,
+				      struct device_node *np)
+{
+	struct regmap *map;
+	struct clk *clk = ERR_PTR(-EINVAL);
+	const char *name = np->name;
+	const char *parent_name;
+	const struct clk_icst_desc *desc;
+	int ret;
+
+	map = syscon_node_to_regmap(parent);
+	if (IS_ERR(map)) {
+		pr_err("no regmap for syscon IM-PD1 ICST clock parent\n");
+		return PTR_ERR(map);
+	}
+
+	if (of_device_is_compatible(np, "arm,impd1-vco1")) {
+		desc = &impd1_icst1_desc;
+	} else if (of_device_is_compatible(np, "arm,impd1-vco2")) {
+		desc = &impd1_icst2_desc;
+	} else {
+		dev_err(dev, "not a clock node %s\n", name);
+		return -ENODEV;
+	}
+
+	of_property_read_string(np, "clock-output-names", &name);
+	parent_name = of_clk_get_parent_name(np, 0);
+	clk = icst_clk_setup(NULL, desc, name, parent_name, map,
+			     ICST_INTEGRATOR_IM_PD1);
+	if (!IS_ERR(clk)) {
+		of_clk_add_provider(np, of_clk_src_simple_get, clk);
+		ret = 0;
+	} else {
+		dev_err(dev, "error setting up IM-PD1 ICST clock\n");
+		ret = PTR_ERR(clk);
+	}
+
+	return ret;
+}
+
+static int integrator_impd1_clk_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	int ret = 0;
+
+	for_each_available_child_of_node_scoped(np, child) {
+		ret = integrator_impd1_clk_spawn(dev, np, child);
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+
+static const struct of_device_id impd1_syscon_match[] = {
+	{ .compatible = "arm,im-pd1-syscon", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, impd1_syscon_match);
+
+static struct platform_driver impd1_clk_driver = {
+	.driver = {
+		.name = "impd1-clk",
+		.of_match_table = impd1_syscon_match,
+	},
+	.probe  = integrator_impd1_clk_probe,
+};
+builtin_platform_driver(impd1_clk_driver);
+
+MODULE_AUTHOR("Linus Walleij <linusw@kernel.org>");
+MODULE_DESCRIPTION("Arm IM-PD1 module clock driver");
+MODULE_LICENSE("GPL v2");