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, 102 insertions, 0 deletions

diff --git a/sound/soc/sof/sof-acpi-dev.c b/sound/soc/sof/sof-acpi-dev.c
new file mode 100644
index 000000000..68bf1b570
--- /dev/null
+++ b/sound/soc/sof/sof-acpi-dev.c
@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause)
+//
+// This file is provided under a dual BSD/GPLv2 license.  When using or
+// redistributing this file, you may do so under either license.
+//
+// Copyright(c) 2018 Intel Corporation
+//
+// Author: Liam Girdwood <liam.r.girdwood@linux.intel.com>
+//
+
+#include <linux/acpi.h>
+#include <linux/firmware.h>
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+#include <sound/soc-acpi.h>
+#include <sound/soc-acpi-intel-match.h>
+#include <sound/sof.h>
+#include "../intel/common/soc-intel-quirks.h"
+#include "ops.h"
+#include "sof-acpi-dev.h"
+
+/* platform specific devices */
+#include "intel/shim.h"
+
+static char *fw_path;
+module_param(fw_path, charp, 0444);
+MODULE_PARM_DESC(fw_path, "deprecated - moved to snd-sof module.");
+
+static char *tplg_path;
+module_param(tplg_path, charp, 0444);
+MODULE_PARM_DESC(tplg_path, "deprecated - moved to snd-sof module.");
+
+static int sof_acpi_debug;
+module_param_named(sof_acpi_debug, sof_acpi_debug, int, 0444);
+MODULE_PARM_DESC(sof_acpi_debug, "SOF ACPI debug options (0x0 all off)");
+
+#define SOF_ACPI_DISABLE_PM_RUNTIME BIT(0)
+
+EXPORT_NS_DEV_PM_OPS(sof_acpi_pm, SND_SOC_SOF_ACPI_DEV) = {
+	SYSTEM_SLEEP_PM_OPS(snd_sof_suspend, snd_sof_resume)
+	RUNTIME_PM_OPS(snd_sof_runtime_suspend, snd_sof_runtime_resume,
+		       snd_sof_runtime_idle)
+};
+
+static void sof_acpi_probe_complete(struct device *dev)
+{
+	dev_dbg(dev, "Completing SOF ACPI probe");
+
+	if (sof_acpi_debug & SOF_ACPI_DISABLE_PM_RUNTIME)
+		return;
+
+	/* allow runtime_pm */
+	pm_runtime_set_autosuspend_delay(dev, SND_SOF_SUSPEND_DELAY_MS);
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_enable(dev);
+}
+
+int sof_acpi_probe(struct platform_device *pdev, const struct sof_dev_desc *desc)
+{
+	struct device *dev = &pdev->dev;
+	struct snd_sof_pdata *sof_pdata;
+
+	dev_dbg(dev, "ACPI DSP detected");
+
+	sof_pdata = devm_kzalloc(dev, sizeof(*sof_pdata), GFP_KERNEL);
+	if (!sof_pdata)
+		return -ENOMEM;
+
+	if (!desc->ops) {
+		dev_err(dev, "error: no matching ACPI descriptor ops\n");
+		return -ENODEV;
+	}
+
+	sof_pdata->desc = desc;
+	sof_pdata->dev = &pdev->dev;
+
+	sof_pdata->ipc_file_profile_base.ipc_type = desc->ipc_default;
+	sof_pdata->ipc_file_profile_base.fw_path = fw_path;
+	sof_pdata->ipc_file_profile_base.tplg_path = tplg_path;
+
+	/* set callback to be called on successful device probe to enable runtime_pm */
+	sof_pdata->sof_probe_complete = sof_acpi_probe_complete;
+
+	/* call sof helper for DSP hardware probe */
+	return snd_sof_device_probe(dev, sof_pdata);
+}
+EXPORT_SYMBOL_NS(sof_acpi_probe, "SND_SOC_SOF_ACPI_DEV");
+
+void sof_acpi_remove(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+
+	if (!(sof_acpi_debug & SOF_ACPI_DISABLE_PM_RUNTIME))
+		pm_runtime_disable(dev);
+
+	/* call sof helper for DSP hardware remove */
+	snd_sof_device_remove(dev);
+}
+EXPORT_SYMBOL_NS(sof_acpi_remove, "SND_SOC_SOF_ACPI_DEV");
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_DESCRIPTION("SOF support for ACPI platforms");