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, 136 insertions, 0 deletions

diff --git a/drivers/usb/dwc2/pci.c b/drivers/usb/dwc2/pci.c
new file mode 100644
index 000000000..f3a1e4232
--- /dev/null
+++ b/drivers/usb/dwc2/pci.c
@@ -0,0 +1,136 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
+/*
+ * pci.c - DesignWare HS OTG Controller PCI driver
+ *
+ * Copyright (C) 2004-2013 Synopsys, Inc.
+ */
+
+/*
+ * Provides the initialization and cleanup entry points for the DWC_otg PCI
+ * driver
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/spinlock.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/pci.h>
+#include <linux/usb.h>
+
+#include <linux/usb/hcd.h>
+#include <linux/usb/ch11.h>
+#include <linux/platform_device.h>
+#include <linux/usb/usb_phy_generic.h>
+
+#include "core.h"
+
+static const char dwc2_driver_name[] = "dwc2-pci";
+
+struct dwc2_pci_glue {
+	struct platform_device *dwc2;
+	struct platform_device *phy;
+};
+
+/**
+ * dwc2_pci_remove() - Provides the cleanup entry points for the DWC_otg PCI
+ * driver
+ *
+ * @pci: The programming view of DWC_otg PCI
+ */
+static void dwc2_pci_remove(struct pci_dev *pci)
+{
+	struct dwc2_pci_glue *glue = pci_get_drvdata(pci);
+
+	platform_device_unregister(glue->dwc2);
+	usb_phy_generic_unregister(glue->phy);
+	pci_set_drvdata(pci, NULL);
+}
+
+static int dwc2_pci_probe(struct pci_dev *pci,
+			  const struct pci_device_id *id)
+{
+	struct resource		res[2];
+	struct platform_device	*dwc2;
+	struct platform_device	*phy;
+	int			ret;
+	struct device		*dev = &pci->dev;
+	struct dwc2_pci_glue	*glue;
+
+	ret = pcim_enable_device(pci);
+	if (ret) {
+		dev_err(dev, "failed to enable pci device\n");
+		return -ENODEV;
+	}
+
+	pci_set_master(pci);
+
+	phy = usb_phy_generic_register();
+	if (IS_ERR(phy)) {
+		dev_err(dev, "error registering generic PHY (%ld)\n",
+			PTR_ERR(phy));
+		return PTR_ERR(phy);
+	}
+
+	dwc2 = platform_device_alloc("dwc2", PLATFORM_DEVID_AUTO);
+	if (!dwc2) {
+		dev_err(dev, "couldn't allocate dwc2 device\n");
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	memset(res, 0x00, sizeof(struct resource) * ARRAY_SIZE(res));
+
+	res[0].start	= pci_resource_start(pci, 0);
+	res[0].end	= pci_resource_end(pci, 0);
+	res[0].name	= "dwc2";
+	res[0].flags	= IORESOURCE_MEM;
+
+	res[1].start	= pci->irq;
+	res[1].name	= "dwc2";
+	res[1].flags	= IORESOURCE_IRQ;
+
+	ret = platform_device_add_resources(dwc2, res, ARRAY_SIZE(res));
+	if (ret) {
+		dev_err(dev, "couldn't add resources to dwc2 device\n");
+		goto err;
+	}
+
+	dwc2->dev.parent = dev;
+
+	glue = devm_kzalloc(dev, sizeof(*glue), GFP_KERNEL);
+	if (!glue) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	ret = platform_device_add(dwc2);
+	if (ret) {
+		dev_err(dev, "failed to register dwc2 device\n");
+		goto err;
+	}
+
+	glue->phy = phy;
+	glue->dwc2 = dwc2;
+	pci_set_drvdata(pci, glue);
+
+	return 0;
+err:
+	usb_phy_generic_unregister(phy);
+	platform_device_put(dwc2);
+	return ret;
+}
+
+static struct pci_driver dwc2_pci_driver = {
+	.name = dwc2_driver_name,
+	.id_table = dwc2_pci_ids,
+	.probe = dwc2_pci_probe,
+	.remove = dwc2_pci_remove,
+};
+
+module_pci_driver(dwc2_pci_driver);
+
+MODULE_DESCRIPTION("DESIGNWARE HS OTG PCI Bus Glue");
+MODULE_AUTHOR("Synopsys, Inc.");
+MODULE_LICENSE("Dual BSD/GPL");