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, 265 insertions, 0 deletions

diff --git a/drivers/firmware/dmi-id.c b/drivers/firmware/dmi-id.c
new file mode 100644
index 000000000..477a37e2e
--- /dev/null
+++ b/drivers/firmware/dmi-id.c
@@ -0,0 +1,265 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Export SMBIOS/DMI info via sysfs to userspace
+ *
+ * Copyright 2007, Lennart Poettering
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/dmi.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+
+struct dmi_device_attribute{
+	struct device_attribute dev_attr;
+	int field;
+};
+#define to_dmi_dev_attr(_dev_attr) \
+	container_of(_dev_attr, struct dmi_device_attribute, dev_attr)
+
+static ssize_t sys_dmi_field_show(struct device *dev,
+				  struct device_attribute *attr,
+				  char *page)
+{
+	int field = to_dmi_dev_attr(attr)->field;
+	ssize_t len;
+	len = scnprintf(page, PAGE_SIZE, "%s\n", dmi_get_system_info(field));
+	page[len-1] = '\n';
+	return len;
+}
+
+#define DMI_ATTR(_name, _mode, _show, _field)			\
+	{ .dev_attr = __ATTR(_name, _mode, _show, NULL),	\
+	  .field = _field }
+
+#define DEFINE_DMI_ATTR_WITH_SHOW(_name, _mode, _field)		\
+static struct dmi_device_attribute sys_dmi_##_name##_attr =	\
+	DMI_ATTR(_name, _mode, sys_dmi_field_show, _field);
+
+DEFINE_DMI_ATTR_WITH_SHOW(bios_vendor,		0444, DMI_BIOS_VENDOR);
+DEFINE_DMI_ATTR_WITH_SHOW(bios_version,		0444, DMI_BIOS_VERSION);
+DEFINE_DMI_ATTR_WITH_SHOW(bios_date,		0444, DMI_BIOS_DATE);
+DEFINE_DMI_ATTR_WITH_SHOW(sys_vendor,		0444, DMI_SYS_VENDOR);
+DEFINE_DMI_ATTR_WITH_SHOW(bios_release,		0444, DMI_BIOS_RELEASE);
+DEFINE_DMI_ATTR_WITH_SHOW(ec_firmware_release,	0444, DMI_EC_FIRMWARE_RELEASE);
+DEFINE_DMI_ATTR_WITH_SHOW(product_name,		0444, DMI_PRODUCT_NAME);
+DEFINE_DMI_ATTR_WITH_SHOW(product_version,	0444, DMI_PRODUCT_VERSION);
+DEFINE_DMI_ATTR_WITH_SHOW(product_serial,	0400, DMI_PRODUCT_SERIAL);
+DEFINE_DMI_ATTR_WITH_SHOW(product_uuid,		0400, DMI_PRODUCT_UUID);
+DEFINE_DMI_ATTR_WITH_SHOW(product_sku,		0444, DMI_PRODUCT_SKU);
+DEFINE_DMI_ATTR_WITH_SHOW(product_family,	0444, DMI_PRODUCT_FAMILY);
+DEFINE_DMI_ATTR_WITH_SHOW(board_vendor,		0444, DMI_BOARD_VENDOR);
+DEFINE_DMI_ATTR_WITH_SHOW(board_name,		0444, DMI_BOARD_NAME);
+DEFINE_DMI_ATTR_WITH_SHOW(board_version,	0444, DMI_BOARD_VERSION);
+DEFINE_DMI_ATTR_WITH_SHOW(board_serial,		0400, DMI_BOARD_SERIAL);
+DEFINE_DMI_ATTR_WITH_SHOW(board_asset_tag,	0444, DMI_BOARD_ASSET_TAG);
+DEFINE_DMI_ATTR_WITH_SHOW(chassis_vendor,	0444, DMI_CHASSIS_VENDOR);
+DEFINE_DMI_ATTR_WITH_SHOW(chassis_type,		0444, DMI_CHASSIS_TYPE);
+DEFINE_DMI_ATTR_WITH_SHOW(chassis_version,	0444, DMI_CHASSIS_VERSION);
+DEFINE_DMI_ATTR_WITH_SHOW(chassis_serial,	0400, DMI_CHASSIS_SERIAL);
+DEFINE_DMI_ATTR_WITH_SHOW(chassis_asset_tag,	0444, DMI_CHASSIS_ASSET_TAG);
+
+static void ascii_filter(char *d, const char *s)
+{
+	/* Filter out characters we don't want to see in the modalias string */
+	for (; *s; s++)
+		if (*s > ' ' && *s < 127 && *s != ':')
+			*(d++) = *s;
+
+	*d = 0;
+}
+
+static ssize_t get_modalias(char *buffer, size_t buffer_size)
+{
+	/*
+	 * Note new fields need to be added at the end to keep compatibility
+	 * with udev's hwdb which does matches on "`cat dmi/id/modalias`*".
+	 */
+	static const struct mafield {
+		const char *prefix;
+		int field;
+	} fields[] = {
+		{ "bvn", DMI_BIOS_VENDOR },
+		{ "bvr", DMI_BIOS_VERSION },
+		{ "bd",  DMI_BIOS_DATE },
+		{ "br",  DMI_BIOS_RELEASE },
+		{ "efr", DMI_EC_FIRMWARE_RELEASE },
+		{ "svn", DMI_SYS_VENDOR },
+		{ "pn",  DMI_PRODUCT_NAME },
+		{ "pvr", DMI_PRODUCT_VERSION },
+		{ "rvn", DMI_BOARD_VENDOR },
+		{ "rn",  DMI_BOARD_NAME },
+		{ "rvr", DMI_BOARD_VERSION },
+		{ "cvn", DMI_CHASSIS_VENDOR },
+		{ "ct",  DMI_CHASSIS_TYPE },
+		{ "cvr", DMI_CHASSIS_VERSION },
+		{ "sku", DMI_PRODUCT_SKU },
+		{ "pfa", DMI_PRODUCT_FAMILY },
+		{ NULL,  DMI_NONE }
+	};
+
+	ssize_t l, left;
+	char *p;
+	const struct mafield *f;
+
+	strcpy(buffer, "dmi");
+	p = buffer + 3; left = buffer_size - 4;
+
+	for (f = fields; f->prefix && left > 0; f++) {
+		const char *c;
+		char *t;
+
+		c = dmi_get_system_info(f->field);
+		if (!c)
+			continue;
+
+		t = kmalloc(strlen(c) + 1, GFP_KERNEL);
+		if (!t)
+			break;
+		ascii_filter(t, c);
+		l = scnprintf(p, left, ":%s%s", f->prefix, t);
+		kfree(t);
+
+		p += l;
+		left -= l;
+	}
+
+	p[0] = ':';
+	p[1] = 0;
+
+	return p - buffer + 1;
+}
+
+static ssize_t sys_dmi_modalias_show(struct device *dev,
+				     struct device_attribute *attr, char *page)
+{
+	ssize_t r;
+	r = get_modalias(page, PAGE_SIZE-1);
+	page[r] = '\n';
+	page[r+1] = 0;
+	return r+1;
+}
+
+static struct device_attribute sys_dmi_modalias_attr =
+	__ATTR(modalias, 0444, sys_dmi_modalias_show, NULL);
+
+static struct attribute *sys_dmi_attributes[DMI_STRING_MAX+2];
+
+static struct attribute_group sys_dmi_attribute_group = {
+	.attrs = sys_dmi_attributes,
+};
+
+static const struct attribute_group* sys_dmi_attribute_groups[] = {
+	&sys_dmi_attribute_group,
+	NULL
+};
+
+static int dmi_dev_uevent(const struct device *dev, struct kobj_uevent_env *env)
+{
+	ssize_t len;
+
+	if (add_uevent_var(env, "MODALIAS="))
+		return -ENOMEM;
+	len = get_modalias(&env->buf[env->buflen - 1],
+			   sizeof(env->buf) - env->buflen);
+	if (len >= (sizeof(env->buf) - env->buflen))
+		return -ENOMEM;
+	env->buflen += len;
+	return 0;
+}
+
+static void dmi_dev_release(struct device *dev)
+{
+	kfree(dev);
+}
+
+static struct class dmi_class = {
+	.name = "dmi",
+	.dev_release = dmi_dev_release,
+	.dev_uevent = dmi_dev_uevent,
+};
+
+static struct device *dmi_dev;
+
+/* Initialization */
+
+#define ADD_DMI_ATTR(_name, _field) \
+	if (dmi_get_system_info(_field)) \
+		sys_dmi_attributes[i++] = &sys_dmi_##_name##_attr.dev_attr.attr;
+
+/* In a separate function to keep gcc 3.2 happy - do NOT merge this in
+   dmi_id_init! */
+static void __init dmi_id_init_attr_table(void)
+{
+	int i;
+
+	/* Not necessarily all DMI fields are available on all
+	 * systems, hence let's built an attribute table of just
+	 * what's available */
+	i = 0;
+	ADD_DMI_ATTR(bios_vendor,       DMI_BIOS_VENDOR);
+	ADD_DMI_ATTR(bios_version,      DMI_BIOS_VERSION);
+	ADD_DMI_ATTR(bios_date,         DMI_BIOS_DATE);
+	ADD_DMI_ATTR(bios_release,      DMI_BIOS_RELEASE);
+	ADD_DMI_ATTR(ec_firmware_release, DMI_EC_FIRMWARE_RELEASE);
+	ADD_DMI_ATTR(sys_vendor,        DMI_SYS_VENDOR);
+	ADD_DMI_ATTR(product_name,      DMI_PRODUCT_NAME);
+	ADD_DMI_ATTR(product_version,   DMI_PRODUCT_VERSION);
+	ADD_DMI_ATTR(product_serial,    DMI_PRODUCT_SERIAL);
+	ADD_DMI_ATTR(product_uuid,      DMI_PRODUCT_UUID);
+	ADD_DMI_ATTR(product_family,    DMI_PRODUCT_FAMILY);
+	ADD_DMI_ATTR(product_sku,       DMI_PRODUCT_SKU);
+	ADD_DMI_ATTR(board_vendor,      DMI_BOARD_VENDOR);
+	ADD_DMI_ATTR(board_name,        DMI_BOARD_NAME);
+	ADD_DMI_ATTR(board_version,     DMI_BOARD_VERSION);
+	ADD_DMI_ATTR(board_serial,      DMI_BOARD_SERIAL);
+	ADD_DMI_ATTR(board_asset_tag,   DMI_BOARD_ASSET_TAG);
+	ADD_DMI_ATTR(chassis_vendor,    DMI_CHASSIS_VENDOR);
+	ADD_DMI_ATTR(chassis_type,      DMI_CHASSIS_TYPE);
+	ADD_DMI_ATTR(chassis_version,   DMI_CHASSIS_VERSION);
+	ADD_DMI_ATTR(chassis_serial,    DMI_CHASSIS_SERIAL);
+	ADD_DMI_ATTR(chassis_asset_tag, DMI_CHASSIS_ASSET_TAG);
+	sys_dmi_attributes[i++] = &sys_dmi_modalias_attr.attr;
+}
+
+static int __init dmi_id_init(void)
+{
+	int ret;
+
+	if (!dmi_available)
+		return -ENODEV;
+
+	dmi_id_init_attr_table();
+
+	ret = class_register(&dmi_class);
+	if (ret)
+		return ret;
+
+	dmi_dev = kzalloc_obj(*dmi_dev);
+	if (!dmi_dev) {
+		ret = -ENOMEM;
+		goto fail_class_unregister;
+	}
+
+	dmi_dev->class = &dmi_class;
+	dev_set_name(dmi_dev, "id");
+	dmi_dev->groups = sys_dmi_attribute_groups;
+
+	ret = device_register(dmi_dev);
+	if (ret)
+		goto fail_put_dmi_dev;
+
+	return 0;
+
+fail_put_dmi_dev:
+	put_device(dmi_dev);
+
+fail_class_unregister:
+	class_unregister(&dmi_class);
+
+	return ret;
+}
+
+arch_initcall(dmi_id_init);