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, 171 insertions, 0 deletions

diff --git a/sound/soc/codecs/max9877.c b/sound/soc/codecs/max9877.c
new file mode 100644
index 000000000..7cd07b6f9
--- /dev/null
+++ b/sound/soc/codecs/max9877.c
@@ -0,0 +1,171 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * max9877.c  --  amp driver for max9877
+ *
+ * Copyright (C) 2009 Samsung Electronics Co.Ltd
+ * Author: Joonyoung Shim <jy0922.shim@samsung.com>
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/regmap.h>
+#include <sound/soc.h>
+#include <sound/tlv.h>
+
+#include "max9877.h"
+
+static const struct reg_default max9877_regs[] = {
+	{ 0, 0x40 },
+	{ 1, 0x00 },
+	{ 2, 0x00 },
+	{ 3, 0x00 },
+	{ 4, 0x49 },
+};
+
+static const DECLARE_TLV_DB_RANGE(max9877_pgain_tlv,
+	0, 1, TLV_DB_SCALE_ITEM(0, 900, 0),
+	2, 2, TLV_DB_SCALE_ITEM(2000, 0, 0)
+);
+
+static const DECLARE_TLV_DB_RANGE(max9877_output_tlv,
+	0, 7, TLV_DB_SCALE_ITEM(-7900, 400, 1),
+	8, 15, TLV_DB_SCALE_ITEM(-4700, 300, 0),
+	16, 23, TLV_DB_SCALE_ITEM(-2300, 200, 0),
+	24, 31, TLV_DB_SCALE_ITEM(-700, 100, 0)
+);
+
+static const char *max9877_out_mode[] = {
+	"INA -> SPK",
+	"INA -> HP",
+	"INA -> SPK and HP",
+	"INB -> SPK",
+	"INB -> HP",
+	"INB -> SPK and HP",
+	"INA + INB -> SPK",
+	"INA + INB -> HP",
+	"INA + INB -> SPK and HP",
+};
+
+static const char *max9877_osc_mode[] = {
+	"1176KHz",
+	"1100KHz",
+	"700KHz",
+};
+
+static const struct soc_enum max9877_enum[] = {
+	SOC_ENUM_SINGLE(MAX9877_OUTPUT_MODE, 0, ARRAY_SIZE(max9877_out_mode),
+			max9877_out_mode),
+	SOC_ENUM_SINGLE(MAX9877_OUTPUT_MODE, MAX9877_OSC_OFFSET,
+			ARRAY_SIZE(max9877_osc_mode), max9877_osc_mode),
+};
+
+static const struct snd_kcontrol_new max9877_controls[] = {
+	SOC_SINGLE_TLV("MAX9877 PGAINA Playback Volume",
+		       MAX9877_INPUT_MODE, 0, 2, 0, max9877_pgain_tlv),
+	SOC_SINGLE_TLV("MAX9877 PGAINB Playback Volume",
+		       MAX9877_INPUT_MODE, 2, 2, 0, max9877_pgain_tlv),
+	SOC_SINGLE_TLV("MAX9877 Amp Speaker Playback Volume",
+		       MAX9877_SPK_VOLUME, 0, 31, 0, max9877_output_tlv),
+	SOC_DOUBLE_R_TLV("MAX9877 Amp HP Playback Volume",
+			 MAX9877_HPL_VOLUME, MAX9877_HPR_VOLUME, 0, 31, 0,
+			 max9877_output_tlv),
+	SOC_SINGLE("MAX9877 INB Stereo Switch",
+		   MAX9877_INPUT_MODE, 4, 1, 1),
+	SOC_SINGLE("MAX9877 INA Stereo Switch",
+		   MAX9877_INPUT_MODE, 5, 1, 1),
+	SOC_SINGLE("MAX9877 Zero-crossing detection Switch",
+		   MAX9877_INPUT_MODE, 6, 1, 0),
+	SOC_SINGLE("MAX9877 Bypass Mode Switch",
+		   MAX9877_OUTPUT_MODE, 6, 1, 0),
+	SOC_ENUM("MAX9877 Output Mode", max9877_enum[0]),
+	SOC_ENUM("MAX9877 Oscillator Mode", max9877_enum[1]),
+};
+
+static const struct snd_soc_dapm_widget max9877_dapm_widgets[] = {
+SND_SOC_DAPM_INPUT("INA1"),
+SND_SOC_DAPM_INPUT("INA2"),
+SND_SOC_DAPM_INPUT("INB1"),
+SND_SOC_DAPM_INPUT("INB2"),
+SND_SOC_DAPM_INPUT("RXIN+"),
+SND_SOC_DAPM_INPUT("RXIN-"),
+
+SND_SOC_DAPM_PGA("SHDN", MAX9877_OUTPUT_MODE, 7, 1, NULL, 0),
+
+SND_SOC_DAPM_OUTPUT("OUT+"),
+SND_SOC_DAPM_OUTPUT("OUT-"),
+SND_SOC_DAPM_OUTPUT("HPL"),
+SND_SOC_DAPM_OUTPUT("HPR"),
+};
+
+static const struct snd_soc_dapm_route max9877_dapm_routes[] = {
+	{ "SHDN", NULL, "INA1" },
+	{ "SHDN", NULL, "INA2" },
+	{ "SHDN", NULL, "INB1" },
+	{ "SHDN", NULL, "INB2" },
+
+	{ "OUT+", NULL, "RXIN+" },
+	{ "OUT+", NULL, "SHDN" },
+
+	{ "OUT-", NULL, "SHDN" },
+	{ "OUT-", NULL, "RXIN-" },
+
+	{ "HPL", NULL, "SHDN" },
+	{ "HPR", NULL, "SHDN" },
+};
+
+static const struct snd_soc_component_driver max9877_component_driver = {
+	.controls = max9877_controls,
+	.num_controls = ARRAY_SIZE(max9877_controls),
+
+	.dapm_widgets = max9877_dapm_widgets,
+	.num_dapm_widgets = ARRAY_SIZE(max9877_dapm_widgets),
+	.dapm_routes = max9877_dapm_routes,
+	.num_dapm_routes = ARRAY_SIZE(max9877_dapm_routes),
+};
+
+static const struct regmap_config max9877_regmap = {
+	.reg_bits = 8,
+	.val_bits = 8,
+
+	.reg_defaults = max9877_regs,
+	.num_reg_defaults = ARRAY_SIZE(max9877_regs),
+	.cache_type = REGCACHE_RBTREE,
+};
+
+static int max9877_i2c_probe(struct i2c_client *client)
+{
+	struct regmap *regmap;
+	int i;
+
+	regmap = devm_regmap_init_i2c(client, &max9877_regmap);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	/* Ensure the device is in reset state */
+	for (i = 0; i < ARRAY_SIZE(max9877_regs); i++)
+		regmap_write(regmap, max9877_regs[i].reg, max9877_regs[i].def);
+
+	return devm_snd_soc_register_component(&client->dev,
+			&max9877_component_driver, NULL, 0);
+}
+
+static const struct i2c_device_id max9877_i2c_id[] = {
+	{ .name = "max9877" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, max9877_i2c_id);
+
+static struct i2c_driver max9877_i2c_driver = {
+	.driver = {
+		.name = "max9877",
+	},
+	.probe = max9877_i2c_probe,
+	.id_table = max9877_i2c_id,
+};
+
+module_i2c_driver(max9877_i2c_driver);
+
+MODULE_DESCRIPTION("ASoC MAX9877 amp driver");
+MODULE_AUTHOR("Joonyoung Shim <jy0922.shim@samsung.com>");
+MODULE_LICENSE("GPL");