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, 148 insertions, 0 deletions

diff --git a/drivers/mfd/tps65086.c b/drivers/mfd/tps65086.c
new file mode 100644
index 000000000..54832e932
--- /dev/null
+++ b/drivers/mfd/tps65086.c
@@ -0,0 +1,148 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2015 Texas Instruments Incorporated - https://www.ti.com/
+ *	Andrew F. Davis <afd@ti.com>
+ *
+ * Based on the TPS65912 driver
+ */
+
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/core.h>
+#include <linux/module.h>
+
+#include <linux/mfd/tps65086.h>
+
+static const struct mfd_cell tps65086_cells[] = {
+	{ .name = "tps65086-regulator", },
+	{ .name = "tps65086-gpio", },
+	{ .name = "tps65086-reset", },
+};
+
+static const struct regmap_range tps65086_yes_ranges[] = {
+	regmap_reg_range(TPS65086_IRQ, TPS65086_IRQ),
+	regmap_reg_range(TPS65086_PMICSTAT, TPS65086_SHUTDNSRC),
+	regmap_reg_range(TPS65086_GPOCTRL, TPS65086_GPOCTRL),
+	regmap_reg_range(TPS65086_PG_STATUS1, TPS65086_OC_STATUS),
+};
+
+static const struct regmap_access_table tps65086_volatile_table = {
+	.yes_ranges = tps65086_yes_ranges,
+	.n_yes_ranges = ARRAY_SIZE(tps65086_yes_ranges),
+};
+
+static const struct regmap_config tps65086_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.cache_type = REGCACHE_MAPLE,
+	.volatile_table = &tps65086_volatile_table,
+	.max_register = TPS65086_OC_STATUS,
+};
+
+static const struct regmap_irq tps65086_irqs[] = {
+	REGMAP_IRQ_REG(TPS65086_IRQ_DIETEMP, 0, TPS65086_IRQ_DIETEMP_MASK),
+	REGMAP_IRQ_REG(TPS65086_IRQ_SHUTDN, 0, TPS65086_IRQ_SHUTDN_MASK),
+	REGMAP_IRQ_REG(TPS65086_IRQ_FAULT, 0, TPS65086_IRQ_FAULT_MASK),
+};
+
+static const struct regmap_irq_chip tps65086_irq_chip = {
+	.name = "tps65086",
+	.status_base = TPS65086_IRQ,
+	.mask_base = TPS65086_IRQ_MASK,
+	.ack_base = TPS65086_IRQ,
+	.init_ack_masked = true,
+	.num_regs = 1,
+	.irqs = tps65086_irqs,
+	.num_irqs = ARRAY_SIZE(tps65086_irqs),
+};
+
+static const struct of_device_id tps65086_of_match_table[] = {
+	{ .compatible = "ti,tps65086", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, tps65086_of_match_table);
+
+static int tps65086_probe(struct i2c_client *client)
+{
+	struct tps65086 *tps;
+	unsigned int version;
+	int ret;
+
+	tps = devm_kzalloc(&client->dev, sizeof(*tps), GFP_KERNEL);
+	if (!tps)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, tps);
+	tps->dev = &client->dev;
+	tps->irq = client->irq;
+
+	tps->regmap = devm_regmap_init_i2c(client, &tps65086_regmap_config);
+	if (IS_ERR(tps->regmap)) {
+		dev_err(tps->dev, "Failed to initialize register map\n");
+		return PTR_ERR(tps->regmap);
+	}
+
+	/* Store device ID to load regulator configuration that fit to IC variant */
+	ret = regmap_read(tps->regmap, TPS65086_DEVICEID1, &tps->chip_id);
+	if (ret) {
+		dev_err(tps->dev, "Failed to read revision register 1\n");
+		return ret;
+	}
+
+	ret = regmap_read(tps->regmap, TPS65086_DEVICEID2, &version);
+	if (ret) {
+		dev_err(tps->dev, "Failed to read revision register 2\n");
+		return ret;
+	}
+
+	dev_info(tps->dev, "Device: TPS65086%01lX, OTP: %c, Rev: %ld\n",
+		 (version & TPS65086_DEVICEID2_PART_MASK),
+		 (char)((version & TPS65086_DEVICEID2_OTP_MASK) >> 4) + 'A',
+		 (version & TPS65086_DEVICEID2_REV_MASK) >> 6);
+
+	if (tps->irq > 0) {
+		ret = regmap_add_irq_chip(tps->regmap, tps->irq, IRQF_ONESHOT, 0,
+					  &tps65086_irq_chip, &tps->irq_data);
+		if (ret) {
+			dev_err(tps->dev, "Failed to register IRQ chip\n");
+			return ret;
+		}
+	}
+
+	ret = mfd_add_devices(tps->dev, PLATFORM_DEVID_AUTO, tps65086_cells,
+			      ARRAY_SIZE(tps65086_cells), NULL, 0,
+			      regmap_irq_get_domain(tps->irq_data));
+	if (ret && tps->irq > 0)
+		regmap_del_irq_chip(tps->irq, tps->irq_data);
+
+	return ret;
+}
+
+static void tps65086_remove(struct i2c_client *client)
+{
+	struct tps65086 *tps = i2c_get_clientdata(client);
+
+	if (tps->irq > 0)
+		regmap_del_irq_chip(tps->irq, tps->irq_data);
+}
+
+static const struct i2c_device_id tps65086_id_table[] = {
+	{ "tps65086" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(i2c, tps65086_id_table);
+
+static struct i2c_driver tps65086_driver = {
+	.driver		= {
+		.name	= "tps65086",
+		.of_match_table = tps65086_of_match_table,
+	},
+	.probe		= tps65086_probe,
+	.remove		= tps65086_remove,
+	.id_table       = tps65086_id_table,
+};
+module_i2c_driver(tps65086_driver);
+
+MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");
+MODULE_DESCRIPTION("TPS65086 PMIC Driver");
+MODULE_LICENSE("GPL v2");