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, 158 insertions, 0 deletions

diff --git a/drivers/spi/spi-altera-platform.c b/drivers/spi/spi-altera-platform.c
new file mode 100644
index 000000000..4fe69ce9d
--- /dev/null
+++ b/drivers/spi/spi-altera-platform.c
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Altera SPI driver
+ *
+ * Copyright (C) 2008 Thomas Chou <thomas@wytron.com.tw>
+ *
+ * Based on spi_s3c24xx.c, which is:
+ * Copyright (c) 2006 Ben Dooks
+ * Copyright (c) 2006 Simtec Electronics
+ *	Ben Dooks <ben@simtec.co.uk>
+ */
+
+#include <linux/interrupt.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/spi/altera.h>
+#include <linux/spi/spi.h>
+#include <linux/io.h>
+#include <linux/of.h>
+
+#define DRV_NAME "spi_altera"
+
+enum altera_spi_type {
+	ALTERA_SPI_TYPE_UNKNOWN,
+	ALTERA_SPI_TYPE_SUBDEV,
+};
+
+static const struct regmap_config spi_altera_config = {
+	.reg_bits = 32,
+	.reg_stride = 4,
+	.val_bits = 32,
+};
+
+static int altera_spi_probe(struct platform_device *pdev)
+{
+	const struct platform_device_id *platid = platform_get_device_id(pdev);
+	struct altera_spi_platform_data *pdata = dev_get_platdata(&pdev->dev);
+	enum altera_spi_type type = ALTERA_SPI_TYPE_UNKNOWN;
+	struct altera_spi *hw;
+	struct spi_controller *host;
+	int err;
+	u16 i;
+
+	host = devm_spi_alloc_host(&pdev->dev, sizeof(struct altera_spi));
+	if (!host)
+		return -ENOMEM;
+
+	/* setup the host state. */
+	host->bus_num = -1;
+
+	if (pdata) {
+		if (pdata->num_chipselect > ALTERA_SPI_MAX_CS) {
+			dev_err(&pdev->dev,
+				"Invalid number of chipselect: %u\n",
+				pdata->num_chipselect);
+			return -EINVAL;
+		}
+
+		host->num_chipselect = pdata->num_chipselect;
+		host->mode_bits = pdata->mode_bits;
+		host->bits_per_word_mask = pdata->bits_per_word_mask;
+	} else {
+		host->num_chipselect = 16;
+		host->mode_bits = SPI_CS_HIGH;
+		host->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 16);
+	}
+
+	hw = spi_controller_get_devdata(host);
+	hw->dev = &pdev->dev;
+
+	if (platid)
+		type = platid->driver_data;
+
+	/* find and map our resources */
+	if (type == ALTERA_SPI_TYPE_SUBDEV) {
+		struct resource *regoff;
+
+		hw->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+		if (!hw->regmap)
+			return dev_err_probe(&pdev->dev, -ENODEV, "get regmap failed\n");
+
+		regoff = platform_get_resource(pdev, IORESOURCE_REG, 0);
+		if (regoff)
+			hw->regoff = regoff->start;
+	} else {
+		void __iomem *res;
+
+		res = devm_platform_ioremap_resource(pdev, 0);
+		if (IS_ERR(res))
+			return PTR_ERR(res);
+
+		hw->regmap = devm_regmap_init_mmio(&pdev->dev, res,
+						   &spi_altera_config);
+		if (IS_ERR(hw->regmap))
+			return dev_err_probe(&pdev->dev, PTR_ERR(hw->regmap),
+					     "regmap mmio init failed\n");
+	}
+
+	altera_spi_init_host(host);
+
+	/* irq is optional */
+	hw->irq = platform_get_irq(pdev, 0);
+	if (hw->irq >= 0) {
+		err = devm_request_irq(&pdev->dev, hw->irq, altera_spi_irq, 0,
+				       pdev->name, host);
+		if (err)
+			return err;
+	}
+
+	err = devm_spi_register_controller(&pdev->dev, host);
+	if (err)
+		return err;
+
+	if (pdata) {
+		for (i = 0; i < pdata->num_devices; i++) {
+			if (!spi_new_device(host, pdata->devices + i))
+				dev_warn(&pdev->dev,
+					 "unable to create SPI device: %s\n",
+					 pdata->devices[i].modalias);
+		}
+	}
+
+	dev_info(&pdev->dev, "regoff %u, irq %d\n", hw->regoff, hw->irq);
+
+	return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id altera_spi_match[] = {
+	{ .compatible = "ALTR,spi-1.0", },
+	{ .compatible = "altr,spi-1.0", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, altera_spi_match);
+#endif /* CONFIG_OF */
+
+static const struct platform_device_id altera_spi_ids[] = {
+	{ .name = DRV_NAME,		.driver_data = ALTERA_SPI_TYPE_UNKNOWN },
+	{ .name = "subdev_spi_altera",	.driver_data = ALTERA_SPI_TYPE_SUBDEV },
+	{ }
+};
+MODULE_DEVICE_TABLE(platform, altera_spi_ids);
+
+static struct platform_driver altera_spi_driver = {
+	.probe = altera_spi_probe,
+	.driver = {
+		.name = DRV_NAME,
+		.pm = NULL,
+		.of_match_table = of_match_ptr(altera_spi_match),
+	},
+	.id_table	= altera_spi_ids,
+};
+module_platform_driver(altera_spi_driver);
+
+MODULE_DESCRIPTION("Altera SPI driver");
+MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
+MODULE_LICENSE("GPL");