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, 106 insertions, 0 deletions

diff --git a/drivers/reset/amlogic/reset-meson.c b/drivers/reset/amlogic/reset-meson.c
new file mode 100644
index 000000000..c303e8590
--- /dev/null
+++ b/drivers/reset/amlogic/reset-meson.c
@@ -0,0 +1,106 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
+/*
+ * Amlogic Meson Reset Controller driver
+ *
+ * Copyright (c) 2016-2024 BayLibre, SAS.
+ * Authors: Neil Armstrong <narmstrong@baylibre.com>
+ *          Jerome Brunet <jbrunet@baylibre.com>
+ */
+
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/reset-controller.h>
+
+#include "reset-meson.h"
+
+static const struct meson_reset_param meson8b_param = {
+	.reset_ops	= &meson_reset_ops,
+	.reset_num	= 256,
+	.reset_offset	= 0x0,
+	.level_offset	= 0x7c,
+	.level_low_reset = true,
+};
+
+static const struct meson_reset_param meson_a1_param = {
+	.reset_ops	= &meson_reset_ops,
+	.reset_num	= 96,
+	.reset_offset	= 0x0,
+	.level_offset	= 0x40,
+	.level_low_reset = true,
+};
+
+static const struct meson_reset_param meson_s4_param = {
+	.reset_ops	= &meson_reset_ops,
+	.reset_num	= 192,
+	.reset_offset	= 0x0,
+	.level_offset	= 0x40,
+	.level_low_reset = true,
+};
+
+static const struct meson_reset_param t7_param = {
+	.reset_ops	= &meson_reset_ops,
+	.reset_num      = 224,
+	.reset_offset	= 0x0,
+	.level_offset   = 0x40,
+	.level_low_reset = true,
+};
+
+static const struct of_device_id meson_reset_dt_ids[] = {
+	 { .compatible = "amlogic,meson8b-reset",    .data = &meson8b_param},
+	 { .compatible = "amlogic,meson-gxbb-reset", .data = &meson8b_param},
+	 { .compatible = "amlogic,meson-axg-reset",  .data = &meson8b_param},
+	 { .compatible = "amlogic,meson-a1-reset",   .data = &meson_a1_param},
+	 { .compatible = "amlogic,meson-s4-reset",   .data = &meson_s4_param},
+	 { .compatible = "amlogic,c3-reset",   .data = &meson_s4_param},
+	 { .compatible = "amlogic,t7-reset",   .data = &t7_param},
+	 { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, meson_reset_dt_ids);
+
+static const struct regmap_config regmap_config = {
+	.reg_bits   = 32,
+	.val_bits   = 32,
+	.reg_stride = 4,
+};
+
+static int meson_reset_probe(struct platform_device *pdev)
+{
+	const struct meson_reset_param *param;
+	struct device *dev = &pdev->dev;
+	struct regmap *map;
+	void __iomem *base;
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	param = device_get_match_data(dev);
+	if (!param)
+		return -ENODEV;
+
+	map = devm_regmap_init_mmio(dev, base, &regmap_config);
+	if (IS_ERR(map))
+		return dev_err_probe(dev, PTR_ERR(map),
+				     "can't init regmap mmio region\n");
+
+	return meson_reset_controller_register(dev, map, param);
+}
+
+static struct platform_driver meson_reset_driver = {
+	.probe	= meson_reset_probe,
+	.driver = {
+		.name		= "meson_reset",
+		.of_match_table	= meson_reset_dt_ids,
+	},
+};
+module_platform_driver(meson_reset_driver);
+
+MODULE_DESCRIPTION("Amlogic Meson Reset Controller driver");
+MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
+MODULE_AUTHOR("Jerome Brunet <jbrunet@baylibre.com>");
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_IMPORT_NS("MESON_RESET");