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, 232 insertions, 0 deletions

diff --git a/sound/soc/codecs/max9768.c b/sound/soc/codecs/max9768.c
new file mode 100644
index 000000000..8621d9bdb
--- /dev/null
+++ b/sound/soc/codecs/max9768.c
@@ -0,0 +1,232 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * MAX9768 AMP driver
+ *
+ * Copyright (C) 2011, 2012 by Wolfram Sang, Pengutronix e.K.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/slab.h>
+#include <linux/gpio/consumer.h>
+#include <linux/regmap.h>
+
+#include <sound/core.h>
+#include <sound/soc.h>
+#include <sound/tlv.h>
+#include <sound/max9768.h>
+
+/* "Registers" */
+#define MAX9768_VOL 0
+#define MAX9768_CTRL 3
+
+/* Commands */
+#define MAX9768_CTRL_PWM 0x15
+#define MAX9768_CTRL_FILTERLESS 0x16
+
+struct max9768 {
+	struct regmap *regmap;
+	struct gpio_desc *mute;
+	struct gpio_desc *shdn;
+	u32 flags;
+};
+
+static const struct reg_default max9768_default_regs[] = {
+	{ 0, 0 },
+	{ 3,  MAX9768_CTRL_FILTERLESS},
+};
+
+static int max9768_get_gpio(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_soc_component *c = snd_kcontrol_chip(kcontrol);
+	struct max9768 *max9768 = snd_soc_component_get_drvdata(c);
+	int val = gpiod_get_value_cansleep(max9768->mute);
+
+	ucontrol->value.integer.value[0] = !val;
+
+	return 0;
+}
+
+static int max9768_set_gpio(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_soc_component *c = snd_kcontrol_chip(kcontrol);
+	struct max9768 *max9768 = snd_soc_component_get_drvdata(c);
+	bool val = !ucontrol->value.integer.value[0];
+	int ret;
+
+	if (val != gpiod_get_value_cansleep(max9768->mute))
+		ret = 1;
+	else
+		ret = 0;
+
+	gpiod_set_value_cansleep(max9768->mute, val);
+
+	return ret;
+}
+
+static const DECLARE_TLV_DB_RANGE(volume_tlv,
+	0, 0, TLV_DB_SCALE_ITEM(-16150, 0, 0),
+	1, 1, TLV_DB_SCALE_ITEM(-9280, 0, 0),
+	2, 2, TLV_DB_SCALE_ITEM(-9030, 0, 0),
+	3, 3, TLV_DB_SCALE_ITEM(-8680, 0, 0),
+	4, 4, TLV_DB_SCALE_ITEM(-8430, 0, 0),
+	5, 5, TLV_DB_SCALE_ITEM(-8080, 0, 0),
+	6, 6, TLV_DB_SCALE_ITEM(-7830, 0, 0),
+	7, 7, TLV_DB_SCALE_ITEM(-7470, 0, 0),
+	8, 8, TLV_DB_SCALE_ITEM(-7220, 0, 0),
+	9, 9, TLV_DB_SCALE_ITEM(-6870, 0, 0),
+	10, 10, TLV_DB_SCALE_ITEM(-6620, 0, 0),
+	11, 11, TLV_DB_SCALE_ITEM(-6270, 0, 0),
+	12, 12, TLV_DB_SCALE_ITEM(-6020, 0, 0),
+	13, 13, TLV_DB_SCALE_ITEM(-5670, 0, 0),
+	14, 14, TLV_DB_SCALE_ITEM(-5420, 0, 0),
+	15, 17, TLV_DB_SCALE_ITEM(-5060, 250, 0),
+	18, 18, TLV_DB_SCALE_ITEM(-4370, 0, 0),
+	19, 19, TLV_DB_SCALE_ITEM(-4210, 0, 0),
+	20, 20, TLV_DB_SCALE_ITEM(-3960, 0, 0),
+	21, 21, TLV_DB_SCALE_ITEM(-3760, 0, 0),
+	22, 22, TLV_DB_SCALE_ITEM(-3600, 0, 0),
+	23, 23, TLV_DB_SCALE_ITEM(-3340, 0, 0),
+	24, 24, TLV_DB_SCALE_ITEM(-3150, 0, 0),
+	25, 25, TLV_DB_SCALE_ITEM(-2980, 0, 0),
+	26, 26, TLV_DB_SCALE_ITEM(-2720, 0, 0),
+	27, 27, TLV_DB_SCALE_ITEM(-2520, 0, 0),
+	28, 30, TLV_DB_SCALE_ITEM(-2350, 190, 0),
+	31, 31, TLV_DB_SCALE_ITEM(-1750, 0, 0),
+	32, 34, TLV_DB_SCALE_ITEM(-1640, 100, 0),
+	35, 37, TLV_DB_SCALE_ITEM(-1310, 110, 0),
+	38, 39, TLV_DB_SCALE_ITEM(-990, 100, 0),
+	40, 40, TLV_DB_SCALE_ITEM(-710, 0, 0),
+	41, 41, TLV_DB_SCALE_ITEM(-600, 0, 0),
+	42, 42, TLV_DB_SCALE_ITEM(-500, 0, 0),
+	43, 43, TLV_DB_SCALE_ITEM(-340, 0, 0),
+	44, 44, TLV_DB_SCALE_ITEM(-190, 0, 0),
+	45, 45, TLV_DB_SCALE_ITEM(-50, 0, 0),
+	46, 46, TLV_DB_SCALE_ITEM(50, 0, 0),
+	47, 50, TLV_DB_SCALE_ITEM(120, 40, 0),
+	51, 57, TLV_DB_SCALE_ITEM(290, 50, 0),
+	58, 58, TLV_DB_SCALE_ITEM(650, 0, 0),
+	59, 62, TLV_DB_SCALE_ITEM(700, 60, 0),
+	63, 63, TLV_DB_SCALE_ITEM(950, 0, 0)
+);
+
+static const struct snd_kcontrol_new max9768_volume[] = {
+	SOC_SINGLE_TLV("Playback Volume", MAX9768_VOL, 0, 63, 0, volume_tlv),
+};
+
+static const struct snd_kcontrol_new max9768_mute[] = {
+	SOC_SINGLE_BOOL_EXT("Playback Switch", 0, max9768_get_gpio, max9768_set_gpio),
+};
+
+static const struct snd_soc_dapm_widget max9768_dapm_widgets[] = {
+SND_SOC_DAPM_INPUT("IN"),
+
+SND_SOC_DAPM_OUTPUT("OUT+"),
+SND_SOC_DAPM_OUTPUT("OUT-"),
+};
+
+static const struct snd_soc_dapm_route max9768_dapm_routes[] = {
+	{ "OUT+", NULL, "IN" },
+	{ "OUT-", NULL, "IN" },
+};
+
+static int max9768_probe(struct snd_soc_component *component)
+{
+	struct max9768 *max9768 = snd_soc_component_get_drvdata(component);
+	int ret;
+
+	if (max9768->flags & MAX9768_FLAG_CLASSIC_PWM) {
+		ret = regmap_write(max9768->regmap, MAX9768_CTRL,
+			MAX9768_CTRL_PWM);
+		if (ret)
+			return ret;
+	}
+
+	if (max9768->mute) {
+		ret = snd_soc_add_component_controls(component, max9768_mute,
+				ARRAY_SIZE(max9768_mute));
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static const struct snd_soc_component_driver max9768_component_driver = {
+	.probe = max9768_probe,
+	.controls = max9768_volume,
+	.num_controls = ARRAY_SIZE(max9768_volume),
+	.dapm_widgets = max9768_dapm_widgets,
+	.num_dapm_widgets = ARRAY_SIZE(max9768_dapm_widgets),
+	.dapm_routes = max9768_dapm_routes,
+	.num_dapm_routes = ARRAY_SIZE(max9768_dapm_routes),
+};
+
+static const struct regmap_config max9768_i2c_regmap_config = {
+	.reg_bits = 2,
+	.val_bits = 6,
+	.max_register = 3,
+	.reg_defaults = max9768_default_regs,
+	.num_reg_defaults = ARRAY_SIZE(max9768_default_regs),
+	.cache_type = REGCACHE_RBTREE,
+};
+
+static int max9768_i2c_probe(struct i2c_client *client)
+{
+	struct max9768 *max9768;
+	struct max9768_pdata *pdata = client->dev.platform_data;
+
+	max9768 = devm_kzalloc(&client->dev, sizeof(*max9768), GFP_KERNEL);
+	if (!max9768)
+		return -ENOMEM;
+
+	/* Mute on powerup to avoid clicks */
+	max9768->mute = devm_gpiod_get_optional(&client->dev,
+						"mute",
+						GPIOD_OUT_HIGH);
+	if (IS_ERR(max9768->mute))
+		return PTR_ERR(max9768->mute);
+	gpiod_set_consumer_name(max9768->mute, "MAX9768 Mute");
+
+	/* Activate chip by releasing shutdown, enables I2C */
+	max9768->shdn = devm_gpiod_get_optional(&client->dev,
+						"shutdown",
+						GPIOD_OUT_HIGH);
+	if (IS_ERR(max9768->shdn))
+		return PTR_ERR(max9768->shdn);
+	gpiod_set_consumer_name(max9768->shdn, "MAX9768 Shutdown");
+
+	if (pdata)
+		max9768->flags = pdata->flags;
+
+	i2c_set_clientdata(client, max9768);
+
+	max9768->regmap = devm_regmap_init_i2c(client, &max9768_i2c_regmap_config);
+	if (IS_ERR(max9768->regmap))
+		return PTR_ERR(max9768->regmap);
+
+	return devm_snd_soc_register_component(&client->dev,
+		&max9768_component_driver, NULL, 0);
+}
+
+static const struct i2c_device_id max9768_i2c_id[] = {
+	{ .name = "max9768" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, max9768_i2c_id);
+
+static struct i2c_driver max9768_i2c_driver = {
+	.driver = {
+		.name = "max9768",
+	},
+	.probe = max9768_i2c_probe,
+	.id_table = max9768_i2c_id,
+};
+module_i2c_driver(max9768_i2c_driver);
+
+MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>");
+MODULE_DESCRIPTION("ASoC MAX9768 amplifier driver");
+MODULE_LICENSE("GPL v2");