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, 181 insertions, 0 deletions

diff --git a/sound/soc/codecs/max98357a.c b/sound/soc/codecs/max98357a.c
new file mode 100644
index 000000000..b0f8043fb
--- /dev/null
+++ b/sound/soc/codecs/max98357a.c
@@ -0,0 +1,181 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2010-2011,2013-2015 The Linux Foundation. All rights reserved.
+ *
+ * max98357a.c -- MAX98357A ALSA SoC Codec driver
+ */
+
+#include <linux/acpi.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <sound/pcm.h>
+#include <sound/soc.h>
+#include <sound/soc-dai.h>
+#include <sound/soc-dapm.h>
+
+struct max98357a_priv {
+	struct gpio_desc *sdmode;
+	unsigned int sdmode_delay;
+	int sdmode_switch;
+};
+
+static int max98357a_daiops_trigger(struct snd_pcm_substream *substream,
+		int cmd, struct snd_soc_dai *dai)
+{
+	struct snd_soc_component *component = dai->component;
+	struct max98357a_priv *max98357a =
+		snd_soc_component_get_drvdata(component);
+
+	if (!max98357a->sdmode)
+		return 0;
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_RESUME:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		mdelay(max98357a->sdmode_delay);
+		if (max98357a->sdmode_switch) {
+			gpiod_set_value(max98357a->sdmode, 1);
+			dev_dbg(component->dev, "set sdmode to 1");
+		}
+		break;
+	case SNDRV_PCM_TRIGGER_STOP:
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+		gpiod_set_value(max98357a->sdmode, 0);
+		dev_dbg(component->dev, "set sdmode to 0");
+		break;
+	}
+
+	return 0;
+}
+
+static int max98357a_sdmode_event(struct snd_soc_dapm_widget *w,
+		struct snd_kcontrol *kcontrol, int event)
+{
+	struct snd_soc_component *component =
+		snd_soc_dapm_to_component(w->dapm);
+	struct max98357a_priv *max98357a =
+		snd_soc_component_get_drvdata(component);
+
+	if (event & SND_SOC_DAPM_POST_PMU)
+		max98357a->sdmode_switch = 1;
+	else if (event & SND_SOC_DAPM_POST_PMD)
+		max98357a->sdmode_switch = 0;
+
+	return 0;
+}
+
+static const struct snd_soc_dapm_widget max98357a_dapm_widgets[] = {
+	SND_SOC_DAPM_OUTPUT("Speaker"),
+	SND_SOC_DAPM_OUT_DRV_E("SD_MODE", SND_SOC_NOPM, 0, 0, NULL, 0,
+			max98357a_sdmode_event,
+			SND_SOC_DAPM_POST_PMU | SND_SOC_DAPM_POST_PMD),
+};
+
+static const struct snd_soc_dapm_route max98357a_dapm_routes[] = {
+	{"SD_MODE", NULL, "HiFi Playback"},
+	{"Speaker", NULL, "SD_MODE"},
+};
+
+static const struct snd_soc_component_driver max98357a_component_driver = {
+	.dapm_widgets		= max98357a_dapm_widgets,
+	.num_dapm_widgets	= ARRAY_SIZE(max98357a_dapm_widgets),
+	.dapm_routes		= max98357a_dapm_routes,
+	.num_dapm_routes	= ARRAY_SIZE(max98357a_dapm_routes),
+	.idle_bias_on		= 1,
+	.use_pmdown_time	= 1,
+	.endianness		= 1,
+};
+
+static const struct snd_soc_dai_ops max98357a_dai_ops = {
+	.trigger        = max98357a_daiops_trigger,
+};
+
+static struct snd_soc_dai_driver max98357a_dai_driver = {
+	.name = "HiFi",
+	.playback = {
+		.stream_name	= "HiFi Playback",
+		.formats	= SNDRV_PCM_FMTBIT_S16 |
+					SNDRV_PCM_FMTBIT_S24 |
+					SNDRV_PCM_FMTBIT_S32,
+		.rates		= SNDRV_PCM_RATE_8000 |
+					SNDRV_PCM_RATE_16000 |
+					SNDRV_PCM_RATE_32000 |
+					SNDRV_PCM_RATE_44100 |
+					SNDRV_PCM_RATE_48000 |
+					SNDRV_PCM_RATE_88200 |
+					SNDRV_PCM_RATE_96000,
+		.rate_min	= 8000,
+		.rate_max	= 96000,
+		.channels_min	= 1,
+		.channels_max	= 2,
+	},
+	.ops    = &max98357a_dai_ops,
+};
+
+static int max98357a_platform_probe(struct platform_device *pdev)
+{
+	struct max98357a_priv *max98357a;
+	int ret;
+
+	max98357a = devm_kzalloc(&pdev->dev, sizeof(*max98357a), GFP_KERNEL);
+	if (!max98357a)
+		return -ENOMEM;
+
+	max98357a->sdmode = devm_gpiod_get_optional(&pdev->dev,
+				"sdmode", GPIOD_OUT_LOW);
+	if (IS_ERR(max98357a->sdmode))
+		return PTR_ERR(max98357a->sdmode);
+
+	ret = device_property_read_u32(&pdev->dev, "sdmode-delay",
+					&max98357a->sdmode_delay);
+	if (ret) {
+		max98357a->sdmode_delay = 0;
+		dev_dbg(&pdev->dev,
+			"no optional property 'sdmode-delay' found, "
+			"default: no delay\n");
+	}
+
+	dev_set_drvdata(&pdev->dev, max98357a);
+
+	return devm_snd_soc_register_component(&pdev->dev,
+			&max98357a_component_driver,
+			&max98357a_dai_driver, 1);
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id max98357a_device_id[] = {
+	{ .compatible = "maxim,max98357a" },
+	{ .compatible = "maxim,max98360a" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, max98357a_device_id);
+#endif
+
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id max98357a_acpi_match[] = {
+	{ "MX98357A", 0 },
+	{ "MX98360A", 0 },
+	{},
+};
+MODULE_DEVICE_TABLE(acpi, max98357a_acpi_match);
+#endif
+
+static struct platform_driver max98357a_platform_driver = {
+	.driver = {
+		.name = "max98357a",
+		.of_match_table = of_match_ptr(max98357a_device_id),
+		.acpi_match_table = ACPI_PTR(max98357a_acpi_match),
+	},
+	.probe	= max98357a_platform_probe,
+};
+module_platform_driver(max98357a_platform_driver);
+
+MODULE_DESCRIPTION("Maxim MAX98357A Codec Driver");
+MODULE_LICENSE("GPL v2");