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/dma/dw/pci.c b/drivers/dma/dw/pci.c
new file mode 100644
index 000000000..a3aae3d1c
--- /dev/null
+++ b/drivers/dma/dw/pci.c
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PCI driver for the Synopsys DesignWare DMA Controller
+ *
+ * Copyright (C) 2013 Intel Corporation
+ * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
+ */
+
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/device.h>
+
+#include "internal.h"
+
+static int dw_pci_probe(struct pci_dev *pdev, const struct pci_device_id *pid)
+{
+	const struct dw_dma_chip_pdata *drv_data = (void *)pid->driver_data;
+	struct dw_dma_chip_pdata *data;
+	struct dw_dma_chip *chip;
+	int ret;
+
+	ret = pcim_enable_device(pdev);
+	if (ret)
+		return ret;
+
+	ret = pcim_iomap_regions(pdev, 1 << 0, pci_name(pdev));
+	if (ret) {
+		dev_err(&pdev->dev, "I/O memory remapping failed\n");
+		return ret;
+	}
+
+	pci_set_master(pdev);
+	pci_try_set_mwi(pdev);
+
+	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
+	if (ret)
+		return ret;
+
+	data = devm_kmemdup(&pdev->dev, drv_data, sizeof(*drv_data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
+	chip->dev = &pdev->dev;
+	chip->id = pdev->devfn;
+	chip->regs = pcim_iomap_table(pdev)[0];
+	chip->irq = pdev->irq;
+	chip->pdata = data->pdata;
+
+	data->chip = chip;
+
+	ret = data->probe(chip);
+	if (ret)
+		return ret;
+
+	pci_set_drvdata(pdev, data);
+
+	dw_dma_acpi_controller_register(chip->dw);
+
+	return 0;
+}
+
+static void dw_pci_remove(struct pci_dev *pdev)
+{
+	struct dw_dma_chip_pdata *data = pci_get_drvdata(pdev);
+	struct dw_dma_chip *chip = data->chip;
+	int ret;
+
+	dw_dma_acpi_controller_free(chip->dw);
+
+	ret = data->remove(chip);
+	if (ret)
+		dev_warn(&pdev->dev, "can't remove device properly: %d\n", ret);
+}
+
+static int dw_pci_suspend_late(struct device *dev)
+{
+	struct dw_dma_chip_pdata *data = dev_get_drvdata(dev);
+	struct dw_dma_chip *chip = data->chip;
+
+	return do_dw_dma_disable(chip);
+};
+
+static int dw_pci_resume_early(struct device *dev)
+{
+	struct dw_dma_chip_pdata *data = dev_get_drvdata(dev);
+	struct dw_dma_chip *chip = data->chip;
+
+	return do_dw_dma_enable(chip);
+};
+
+static const struct dev_pm_ops dw_pci_dev_pm_ops = {
+	LATE_SYSTEM_SLEEP_PM_OPS(dw_pci_suspend_late, dw_pci_resume_early)
+};
+
+static const struct pci_device_id dw_pci_id_table[] = {
+	/* Medfield (GPDMA) */
+	{ PCI_VDEVICE(INTEL, 0x0827), (kernel_ulong_t)&dw_dma_chip_pdata },
+
+	/* BayTrail */
+	{ PCI_VDEVICE(INTEL, 0x0f06), (kernel_ulong_t)&dw_dma_chip_pdata },
+	{ PCI_VDEVICE(INTEL, 0x0f40), (kernel_ulong_t)&dw_dma_chip_pdata },
+
+	/* Merrifield */
+	{ PCI_VDEVICE(INTEL, 0x11a2), (kernel_ulong_t)&idma32_chip_pdata },
+
+	/* Braswell */
+	{ PCI_VDEVICE(INTEL, 0x2286), (kernel_ulong_t)&dw_dma_chip_pdata },
+	{ PCI_VDEVICE(INTEL, 0x22c0), (kernel_ulong_t)&dw_dma_chip_pdata },
+
+	/* Elkhart Lake iDMA 32-bit (PSE DMA) */
+	{ PCI_VDEVICE(INTEL, 0x4bb4), (kernel_ulong_t)&xbar_chip_pdata },
+	{ PCI_VDEVICE(INTEL, 0x4bb5), (kernel_ulong_t)&xbar_chip_pdata },
+	{ PCI_VDEVICE(INTEL, 0x4bb6), (kernel_ulong_t)&xbar_chip_pdata },
+
+	/* Haswell */
+	{ PCI_VDEVICE(INTEL, 0x9c60), (kernel_ulong_t)&dw_dma_chip_pdata },
+
+	/* Broadwell */
+	{ PCI_VDEVICE(INTEL, 0x9ce0), (kernel_ulong_t)&dw_dma_chip_pdata },
+
+	{ }
+};
+MODULE_DEVICE_TABLE(pci, dw_pci_id_table);
+
+static struct pci_driver dw_pci_driver = {
+	.name		= "dw_dmac_pci",
+	.id_table	= dw_pci_id_table,
+	.probe		= dw_pci_probe,
+	.remove		= dw_pci_remove,
+	.driver	= {
+		.pm	= pm_sleep_ptr(&dw_pci_dev_pm_ops),
+	},
+};
+
+module_pci_driver(dw_pci_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Synopsys DesignWare DMA Controller PCI driver");
+MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@linux.intel.com>");