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, 177 insertions, 0 deletions

diff --git a/drivers/usb/host/ehci-grlib.c b/drivers/usb/host/ehci-grlib.c
new file mode 100644
index 000000000..bd9762eaa
--- /dev/null
+++ b/drivers/usb/host/ehci-grlib.c
@@ -0,0 +1,177 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Driver for Aeroflex Gaisler GRLIB GRUSBHC EHCI host controller
+ *
+ * GRUSBHC is typically found on LEON/GRLIB SoCs
+ *
+ * (c) Jan Andersson <jan@gaisler.com>
+ *
+ * Based on ehci-ppc-of.c which is:
+ * (c) Valentine Barshak <vbarshak@ru.mvista.com>
+ * and in turn based on "ehci-ppc-soc.c" by Stefan Roese <sr@denx.de>
+ * and "ohci-ppc-of.c" by Sylvain Munaut <tnt@246tNt.com>
+ */
+
+#include <linux/err.h>
+#include <linux/signal.h>
+
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+
+#define GRUSBHC_HCIVERSION 0x0100 /* Known value of cap. reg. HCIVERSION */
+
+static const struct hc_driver ehci_grlib_hc_driver = {
+	.description		= hcd_name,
+	.product_desc		= "GRLIB GRUSBHC EHCI",
+	.hcd_priv_size		= sizeof(struct ehci_hcd),
+
+	/*
+	 * generic hardware linkage
+	 */
+	.irq			= ehci_irq,
+	.flags			= HCD_MEMORY | HCD_DMA | HCD_USB2 | HCD_BH,
+
+	/*
+	 * basic lifecycle operations
+	 */
+	.reset			= ehci_setup,
+	.start			= ehci_run,
+	.stop			= ehci_stop,
+	.shutdown		= ehci_shutdown,
+
+	/*
+	 * managing i/o requests and associated device resources
+	 */
+	.urb_enqueue		= ehci_urb_enqueue,
+	.urb_dequeue		= ehci_urb_dequeue,
+	.endpoint_disable	= ehci_endpoint_disable,
+	.endpoint_reset		= ehci_endpoint_reset,
+
+	/*
+	 * scheduling support
+	 */
+	.get_frame_number	= ehci_get_frame,
+
+	/*
+	 * root hub support
+	 */
+	.hub_status_data	= ehci_hub_status_data,
+	.hub_control		= ehci_hub_control,
+#ifdef	CONFIG_PM
+	.bus_suspend		= ehci_bus_suspend,
+	.bus_resume		= ehci_bus_resume,
+#endif
+	.relinquish_port	= ehci_relinquish_port,
+	.port_handed_over	= ehci_port_handed_over,
+
+	.clear_tt_buffer_complete	= ehci_clear_tt_buffer_complete,
+};
+
+
+static int ehci_hcd_grlib_probe(struct platform_device *op)
+{
+	struct device_node *dn = op->dev.of_node;
+	struct usb_hcd *hcd;
+	struct ehci_hcd	*ehci = NULL;
+	struct resource res;
+	u32 hc_capbase;
+	int irq;
+	int rv;
+
+	if (usb_disabled())
+		return -ENODEV;
+
+	dev_dbg(&op->dev, "initializing GRUSBHC EHCI USB Controller\n");
+
+	rv = of_address_to_resource(dn, 0, &res);
+	if (rv)
+		return rv;
+
+	/* usb_create_hcd requires dma_mask != NULL */
+	op->dev.dma_mask = &op->dev.coherent_dma_mask;
+	hcd = usb_create_hcd(&ehci_grlib_hc_driver, &op->dev,
+			"GRUSBHC EHCI USB");
+	if (!hcd)
+		return -ENOMEM;
+
+	hcd->rsrc_start = res.start;
+	hcd->rsrc_len = resource_size(&res);
+
+	irq = irq_of_parse_and_map(dn, 0);
+	if (!irq) {
+		dev_err(&op->dev, "%s: irq_of_parse_and_map failed\n",
+			__FILE__);
+		rv = -EBUSY;
+		goto err_irq;
+	}
+
+	hcd->regs = devm_ioremap_resource(&op->dev, &res);
+	if (IS_ERR(hcd->regs)) {
+		rv = PTR_ERR(hcd->regs);
+		goto err_ioremap;
+	}
+
+	ehci = hcd_to_ehci(hcd);
+
+	ehci->caps = hcd->regs;
+
+	/* determine endianness of this implementation */
+	hc_capbase = ehci_readl(ehci, &ehci->caps->hc_capbase);
+	if (HC_VERSION(ehci, hc_capbase) != GRUSBHC_HCIVERSION) {
+		ehci->big_endian_mmio = 1;
+		ehci->big_endian_desc = 1;
+		ehci->big_endian_capbase = 1;
+	}
+
+	rv = usb_add_hcd(hcd, irq, 0);
+	if (rv)
+		goto err_ioremap;
+
+	device_wakeup_enable(hcd->self.controller);
+	return 0;
+
+err_ioremap:
+	irq_dispose_mapping(irq);
+err_irq:
+	usb_put_hcd(hcd);
+
+	return rv;
+}
+
+
+static void ehci_hcd_grlib_remove(struct platform_device *op)
+{
+	struct usb_hcd *hcd = platform_get_drvdata(op);
+
+	dev_dbg(&op->dev, "stopping GRLIB GRUSBHC EHCI USB Controller\n");
+
+	usb_remove_hcd(hcd);
+
+	irq_dispose_mapping(hcd->irq);
+
+	usb_put_hcd(hcd);
+}
+
+
+static const struct of_device_id ehci_hcd_grlib_of_match[] = {
+	{
+		.name = "GAISLER_EHCI",
+	 },
+	{
+		.name = "01_026",
+	 },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ehci_hcd_grlib_of_match);
+
+
+static struct platform_driver ehci_grlib_driver = {
+	.probe		= ehci_hcd_grlib_probe,
+	.remove		= ehci_hcd_grlib_remove,
+	.shutdown	= usb_hcd_platform_shutdown,
+	.driver = {
+		.name = "grlib-ehci",
+		.of_match_table = ehci_hcd_grlib_of_match,
+	},
+};