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, 145 insertions, 0 deletions

diff --git a/drivers/reset/reset-zynqmp.c b/drivers/reset/reset-zynqmp.c
new file mode 100644
index 000000000..c770ea3a1
--- /dev/null
+++ b/drivers/reset/reset-zynqmp.c
@@ -0,0 +1,145 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018 Xilinx, Inc.
+ *
+ */
+
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+#include <linux/firmware/xlnx-zynqmp.h>
+
+#define ZYNQMP_NR_RESETS (ZYNQMP_PM_RESET_END - ZYNQMP_PM_RESET_START)
+#define ZYNQMP_RESET_ID ZYNQMP_PM_RESET_START
+#define VERSAL_NR_RESETS	95
+#define VERSAL_NET_NR_RESETS	176
+
+struct zynqmp_reset_soc_data {
+	u32 reset_id;
+	u32 num_resets;
+};
+
+struct zynqmp_reset_data {
+	struct reset_controller_dev rcdev;
+	const struct zynqmp_reset_soc_data *data;
+};
+
+static inline struct zynqmp_reset_data *
+to_zynqmp_reset_data(struct reset_controller_dev *rcdev)
+{
+	return container_of(rcdev, struct zynqmp_reset_data, rcdev);
+}
+
+static int zynqmp_reset_assert(struct reset_controller_dev *rcdev,
+			       unsigned long id)
+{
+	struct zynqmp_reset_data *priv = to_zynqmp_reset_data(rcdev);
+
+	return zynqmp_pm_reset_assert(priv->data->reset_id + id,
+				      PM_RESET_ACTION_ASSERT);
+}
+
+static int zynqmp_reset_deassert(struct reset_controller_dev *rcdev,
+				 unsigned long id)
+{
+	struct zynqmp_reset_data *priv = to_zynqmp_reset_data(rcdev);
+
+	return zynqmp_pm_reset_assert(priv->data->reset_id + id,
+				      PM_RESET_ACTION_RELEASE);
+}
+
+static int zynqmp_reset_status(struct reset_controller_dev *rcdev,
+			       unsigned long id)
+{
+	struct zynqmp_reset_data *priv = to_zynqmp_reset_data(rcdev);
+	int err;
+	u32 val;
+
+	err = zynqmp_pm_reset_get_status(priv->data->reset_id + id, &val);
+	if (err)
+		return err;
+
+	return val;
+}
+
+static int zynqmp_reset_reset(struct reset_controller_dev *rcdev,
+			      unsigned long id)
+{
+	struct zynqmp_reset_data *priv = to_zynqmp_reset_data(rcdev);
+
+	return zynqmp_pm_reset_assert(priv->data->reset_id + id,
+				      PM_RESET_ACTION_PULSE);
+}
+
+static int zynqmp_reset_of_xlate(struct reset_controller_dev *rcdev,
+				 const struct of_phandle_args *reset_spec)
+{
+	return reset_spec->args[0];
+}
+
+static const struct zynqmp_reset_soc_data zynqmp_reset_data = {
+	.reset_id = ZYNQMP_RESET_ID,
+	.num_resets = ZYNQMP_NR_RESETS,
+};
+
+static const struct zynqmp_reset_soc_data versal_reset_data = {
+	.reset_id = 0,
+	.num_resets = VERSAL_NR_RESETS,
+};
+
+static const struct zynqmp_reset_soc_data versal_net_reset_data = {
+	.reset_id = 0,
+	.num_resets = VERSAL_NET_NR_RESETS,
+};
+
+static const struct reset_control_ops zynqmp_reset_ops = {
+	.reset = zynqmp_reset_reset,
+	.assert = zynqmp_reset_assert,
+	.deassert = zynqmp_reset_deassert,
+	.status = zynqmp_reset_status,
+};
+
+static int zynqmp_reset_probe(struct platform_device *pdev)
+{
+	struct zynqmp_reset_data *priv;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->data = of_device_get_match_data(&pdev->dev);
+	if (!priv->data)
+		return -EINVAL;
+
+	priv->rcdev.ops = &zynqmp_reset_ops;
+	priv->rcdev.owner = THIS_MODULE;
+	priv->rcdev.of_node = pdev->dev.of_node;
+	priv->rcdev.nr_resets = priv->data->num_resets;
+	priv->rcdev.of_reset_n_cells = 1;
+	priv->rcdev.of_xlate = zynqmp_reset_of_xlate;
+
+	return devm_reset_controller_register(&pdev->dev, &priv->rcdev);
+}
+
+static const struct of_device_id zynqmp_reset_dt_ids[] = {
+	{ .compatible = "xlnx,zynqmp-reset", .data = &zynqmp_reset_data, },
+	{ .compatible = "xlnx,versal-reset", .data = &versal_reset_data, },
+	{ .compatible = "xlnx,versal-net-reset", .data = &versal_net_reset_data, },
+	{ /* sentinel */ },
+};
+
+static struct platform_driver zynqmp_reset_driver = {
+	.probe	= zynqmp_reset_probe,
+	.driver = {
+		.name		= KBUILD_MODNAME,
+		.of_match_table	= zynqmp_reset_dt_ids,
+	},
+};
+
+static int __init zynqmp_reset_init(void)
+{
+	return platform_driver_register(&zynqmp_reset_driver);
+}
+
+arch_initcall(zynqmp_reset_init);