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, 267 insertions, 0 deletions

diff --git a/drivers/extcon/devres.c b/drivers/extcon/devres.c
new file mode 100644
index 000000000..f9d52e8ec
--- /dev/null
+++ b/drivers/extcon/devres.c
@@ -0,0 +1,267 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * drivers/extcon/devres.c - EXTCON device's resource management
+ *
+ * Copyright (C) 2016 Samsung Electronics
+ * Author: Chanwoo Choi <cw00.choi@samsung.com>
+ */
+
+#include "extcon.h"
+
+static int devm_extcon_dev_match(struct device *dev, void *res, void *data)
+{
+	struct extcon_dev **r = res;
+
+	if (WARN_ON(!r || !*r))
+		return 0;
+
+	return *r == data;
+}
+
+static void devm_extcon_dev_release(struct device *dev, void *res)
+{
+	extcon_dev_free(*(struct extcon_dev **)res);
+}
+
+
+static void devm_extcon_dev_unreg(struct device *dev, void *res)
+{
+	extcon_dev_unregister(*(struct extcon_dev **)res);
+}
+
+struct extcon_dev_notifier_devres {
+	struct extcon_dev *edev;
+	unsigned int id;
+	struct notifier_block *nb;
+};
+
+static void devm_extcon_dev_notifier_unreg(struct device *dev, void *res)
+{
+	struct extcon_dev_notifier_devres *this = res;
+
+	extcon_unregister_notifier(this->edev, this->id, this->nb);
+}
+
+static void devm_extcon_dev_notifier_all_unreg(struct device *dev, void *res)
+{
+	struct extcon_dev_notifier_devres *this = res;
+
+	extcon_unregister_notifier_all(this->edev, this->nb);
+}
+
+/**
+ * devm_extcon_dev_allocate - Allocate managed extcon device
+ * @dev:		the device owning the extcon device being created
+ * @supported_cable:	the array of the supported external connectors
+ *			ending with EXTCON_NONE.
+ *
+ * This function manages automatically the memory of extcon device using device
+ * resource management and simplify the control of freeing the memory of extcon
+ * device.
+ *
+ * Returns the pointer memory of allocated extcon_dev if success
+ * or ERR_PTR(err) if fail
+ */
+struct extcon_dev *devm_extcon_dev_allocate(struct device *dev,
+					const unsigned int *supported_cable)
+{
+	struct extcon_dev **ptr, *edev;
+
+	ptr = devres_alloc(devm_extcon_dev_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+
+	edev = extcon_dev_allocate(supported_cable);
+	if (IS_ERR(edev)) {
+		devres_free(ptr);
+		return edev;
+	}
+
+	edev->dev.parent = dev;
+
+	*ptr = edev;
+	devres_add(dev, ptr);
+
+	return edev;
+}
+EXPORT_SYMBOL_GPL(devm_extcon_dev_allocate);
+
+/**
+ * devm_extcon_dev_free() - Resource-managed extcon_dev_unregister()
+ * @dev:	the device owning the extcon device being created
+ * @edev:	the extcon device to be freed
+ *
+ * Free the memory that is allocated with devm_extcon_dev_allocate()
+ * function.
+ */
+void devm_extcon_dev_free(struct device *dev, struct extcon_dev *edev)
+{
+	WARN_ON(devres_release(dev, devm_extcon_dev_release,
+			       devm_extcon_dev_match, edev));
+}
+EXPORT_SYMBOL_GPL(devm_extcon_dev_free);
+
+/**
+ * devm_extcon_dev_register() - Resource-managed extcon_dev_register()
+ * @dev:	the device owning the extcon device being created
+ * @edev:	the extcon device to be registered
+ *
+ * this function, that extcon device is automatically unregistered on driver
+ * detach. Internally this function calls extcon_dev_register() function.
+ * To get more information, refer that function.
+ *
+ * If extcon device is registered with this function and the device needs to be
+ * unregistered separately, devm_extcon_dev_unregister() should be used.
+ *
+ * Returns 0 if success or negaive error number if failure.
+ */
+int devm_extcon_dev_register(struct device *dev, struct extcon_dev *edev)
+{
+	struct extcon_dev **ptr;
+	int ret;
+
+	ptr = devres_alloc(devm_extcon_dev_unreg, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+
+	ret = extcon_dev_register(edev);
+	if (ret) {
+		devres_free(ptr);
+		return ret;
+	}
+
+	*ptr = edev;
+	devres_add(dev, ptr);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(devm_extcon_dev_register);
+
+/**
+ * devm_extcon_dev_unregister() - Resource-managed extcon_dev_unregister()
+ * @dev:	the device owning the extcon device being created
+ * @edev:	the extcon device to unregistered
+ *
+ * Unregister extcon device that is registered with devm_extcon_dev_register()
+ * function.
+ */
+void devm_extcon_dev_unregister(struct device *dev, struct extcon_dev *edev)
+{
+	WARN_ON(devres_release(dev, devm_extcon_dev_unreg,
+			       devm_extcon_dev_match, edev));
+}
+EXPORT_SYMBOL_GPL(devm_extcon_dev_unregister);
+
+/**
+ * devm_extcon_register_notifier() - Resource-managed extcon_register_notifier()
+ * @dev:	the device owning the extcon device being created
+ * @edev:	the extcon device
+ * @id:		the unique id among the extcon enumeration
+ * @nb:		a notifier block to be registered
+ *
+ * This function manages automatically the notifier of extcon device using
+ * device resource management and simplify the control of unregistering
+ * the notifier of extcon device.
+ *
+ * Note that the second parameter given to the callback of nb (val) is
+ * "old_state", not the current state. The current state can be retrieved
+ * by looking at the third pameter (edev pointer)'s state value.
+ *
+ * Returns 0 if success or negaive error number if failure.
+ */
+int devm_extcon_register_notifier(struct device *dev, struct extcon_dev *edev,
+				unsigned int id, struct notifier_block *nb)
+{
+	struct extcon_dev_notifier_devres *ptr;
+	int ret;
+
+	ptr = devres_alloc(devm_extcon_dev_notifier_unreg, sizeof(*ptr),
+				GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+
+	ret = extcon_register_notifier(edev, id, nb);
+	if (ret) {
+		devres_free(ptr);
+		return ret;
+	}
+
+	ptr->edev = edev;
+	ptr->id = id;
+	ptr->nb = nb;
+	devres_add(dev, ptr);
+
+	return 0;
+}
+EXPORT_SYMBOL(devm_extcon_register_notifier);
+
+/**
+ * devm_extcon_unregister_notifier()
+ *			- Resource-managed extcon_unregister_notifier()
+ * @dev:	the device owning the extcon device being created
+ * @edev:	the extcon device
+ * @id:		the unique id among the extcon enumeration
+ * @nb:		a notifier block to be registered
+ */
+void devm_extcon_unregister_notifier(struct device *dev,
+				struct extcon_dev *edev, unsigned int id,
+				struct notifier_block *nb)
+{
+	WARN_ON(devres_release(dev, devm_extcon_dev_notifier_unreg,
+			       devm_extcon_dev_match, edev));
+}
+EXPORT_SYMBOL(devm_extcon_unregister_notifier);
+
+/**
+ * devm_extcon_register_notifier_all()
+ *		- Resource-managed extcon_register_notifier_all()
+ * @dev:	the device owning the extcon device being created
+ * @edev:	the extcon device
+ * @nb:		a notifier block to be registered
+ *
+ * This function manages automatically the notifier of extcon device using
+ * device resource management and simplify the control of unregistering
+ * the notifier of extcon device. To get more information, refer that function.
+ *
+ * Returns 0 if success or negaive error number if failure.
+ */
+int devm_extcon_register_notifier_all(struct device *dev, struct extcon_dev *edev,
+				struct notifier_block *nb)
+{
+	struct extcon_dev_notifier_devres *ptr;
+	int ret;
+
+	ptr = devres_alloc(devm_extcon_dev_notifier_all_unreg, sizeof(*ptr),
+				GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+
+	ret = extcon_register_notifier_all(edev, nb);
+	if (ret) {
+		devres_free(ptr);
+		return ret;
+	}
+
+	ptr->edev = edev;
+	ptr->nb = nb;
+	devres_add(dev, ptr);
+
+	return 0;
+}
+EXPORT_SYMBOL(devm_extcon_register_notifier_all);
+
+/**
+ * devm_extcon_unregister_notifier_all()
+ *		- Resource-managed extcon_unregister_notifier_all()
+ * @dev:	the device owning the extcon device being created
+ * @edev:	the extcon device
+ * @nb:		a notifier block to be registered
+ */
+void devm_extcon_unregister_notifier_all(struct device *dev,
+				struct extcon_dev *edev,
+				struct notifier_block *nb)
+{
+	WARN_ON(devres_release(dev, devm_extcon_dev_notifier_all_unreg,
+			       devm_extcon_dev_match, edev));
+}
+EXPORT_SYMBOL(devm_extcon_unregister_notifier_all);