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, 143 insertions, 0 deletions

diff --git a/drivers/mfd/madera-spi.c b/drivers/mfd/madera-spi.c
new file mode 100644
index 000000000..3fffa21ce
--- /dev/null
+++ b/drivers/mfd/madera-spi.c
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * SPI bus interface to Cirrus Logic Madera codecs
+ *
+ * Copyright (C) 2015-2018 Cirrus Logic
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+
+#include <linux/mfd/madera/core.h>
+
+#include "madera.h"
+
+static int madera_spi_probe(struct spi_device *spi)
+{
+	struct madera *madera;
+	const struct regmap_config *regmap_16bit_config = NULL;
+	const struct regmap_config *regmap_32bit_config = NULL;
+	unsigned long type;
+	const char *name;
+	int ret;
+
+	type = (unsigned long)spi_get_device_match_data(spi);
+	switch (type) {
+	case CS47L15:
+		if (IS_ENABLED(CONFIG_MFD_CS47L15)) {
+			regmap_16bit_config = &cs47l15_16bit_spi_regmap;
+			regmap_32bit_config = &cs47l15_32bit_spi_regmap;
+		}
+		break;
+	case CS47L35:
+		if (IS_ENABLED(CONFIG_MFD_CS47L35)) {
+			regmap_16bit_config = &cs47l35_16bit_spi_regmap;
+			regmap_32bit_config = &cs47l35_32bit_spi_regmap;
+		}
+		break;
+	case CS47L85:
+	case WM1840:
+		if (IS_ENABLED(CONFIG_MFD_CS47L85)) {
+			regmap_16bit_config = &cs47l85_16bit_spi_regmap;
+			regmap_32bit_config = &cs47l85_32bit_spi_regmap;
+		}
+		break;
+	case CS47L90:
+	case CS47L91:
+		if (IS_ENABLED(CONFIG_MFD_CS47L90)) {
+			regmap_16bit_config = &cs47l90_16bit_spi_regmap;
+			regmap_32bit_config = &cs47l90_32bit_spi_regmap;
+		}
+		break;
+	case CS42L92:
+	case CS47L92:
+	case CS47L93:
+		if (IS_ENABLED(CONFIG_MFD_CS47L92)) {
+			regmap_16bit_config = &cs47l92_16bit_spi_regmap;
+			regmap_32bit_config = &cs47l92_32bit_spi_regmap;
+		}
+		break;
+	default:
+		dev_err(&spi->dev,
+			"Unknown Madera SPI device type %ld\n", type);
+		return -EINVAL;
+	}
+
+	name = madera_name_from_type(type);
+
+	if (!regmap_16bit_config) {
+		/* it's polite to say which codec isn't built into the kernel */
+		dev_err(&spi->dev,
+			"Kernel does not include support for %s\n", name);
+		return -EINVAL;
+	}
+
+	madera = devm_kzalloc(&spi->dev, sizeof(*madera), GFP_KERNEL);
+	if (!madera)
+		return -ENOMEM;
+
+	madera->regmap = devm_regmap_init_spi(spi, regmap_16bit_config);
+	if (IS_ERR(madera->regmap)) {
+		ret = PTR_ERR(madera->regmap);
+		dev_err(&spi->dev,
+			"Failed to allocate 16-bit register map: %d\n",	ret);
+		return ret;
+	}
+
+	madera->regmap_32bit = devm_regmap_init_spi(spi, regmap_32bit_config);
+	if (IS_ERR(madera->regmap_32bit)) {
+		ret = PTR_ERR(madera->regmap_32bit);
+		dev_err(&spi->dev,
+			"Failed to allocate 32-bit register map: %d\n",	ret);
+		return ret;
+	}
+
+	madera->type = type;
+	madera->type_name = name;
+	madera->dev = &spi->dev;
+	madera->irq = spi->irq;
+
+	return madera_dev_init(madera);
+}
+
+static void madera_spi_remove(struct spi_device *spi)
+{
+	struct madera *madera = spi_get_drvdata(spi);
+
+	madera_dev_exit(madera);
+}
+
+static const struct spi_device_id madera_spi_ids[] = {
+	{ .name = "cs47l15", .driver_data = CS47L15 },
+	{ .name = "cs47l35", .driver_data = CS47L35 },
+	{ .name = "cs47l85", .driver_data = CS47L85 },
+	{ .name = "cs47l90", .driver_data = CS47L90 },
+	{ .name = "cs47l91", .driver_data = CS47L91 },
+	{ .name = "cs42l92", .driver_data = CS42L92 },
+	{ .name = "cs47l92", .driver_data = CS47L92 },
+	{ .name = "cs47l93", .driver_data = CS47L93 },
+	{ .name = "wm1840", .driver_data = WM1840 },
+	{ }
+};
+MODULE_DEVICE_TABLE(spi, madera_spi_ids);
+
+static struct spi_driver madera_spi_driver = {
+	.driver = {
+		.name	= "madera",
+		.pm	= &madera_pm_ops,
+		.of_match_table	= of_match_ptr(madera_of_match),
+	},
+	.probe		= madera_spi_probe,
+	.remove		= madera_spi_remove,
+	.id_table	= madera_spi_ids,
+};
+
+module_spi_driver(madera_spi_driver);
+
+MODULE_DESCRIPTION("Madera SPI bus interface");
+MODULE_AUTHOR("Richard Fitzgerald <rf@opensource.cirrus.com>");
+MODULE_LICENSE("GPL v2");