From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops 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 --- drivers/mfd/act8945a.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 91 insertions(+) create mode 100644 drivers/mfd/act8945a.c (limited to 'drivers/mfd/act8945a.c') diff --git a/drivers/mfd/act8945a.c b/drivers/mfd/act8945a.c new file mode 100644 index 000000000..cafefb445 --- /dev/null +++ b/drivers/mfd/act8945a.c @@ -0,0 +1,91 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * MFD driver for Active-semi ACT8945a PMIC + * + * Copyright (C) 2015 Atmel Corporation. + * + * Author: Wenyou Yang + */ + +#include +#include +#include +#include +#include + +static const struct mfd_cell act8945a_devs[] = { + { + .name = "act8945a-regulator", + }, + { + .name = "act8945a-charger", + .of_compatible = "active-semi,act8945a-charger", + }, +}; + +static const struct regmap_config act8945a_regmap_config = { + .reg_bits = 8, + .val_bits = 8, +}; + +static int act8945a_i2c_probe(struct i2c_client *i2c) +{ + int ret; + struct regmap *regmap; + + regmap = devm_regmap_init_i2c(i2c, &act8945a_regmap_config); + if (IS_ERR(regmap)) { + ret = PTR_ERR(regmap); + dev_err(&i2c->dev, "regmap init failed: %d\n", ret); + return ret; + } + + i2c_set_clientdata(i2c, regmap); + + ret = devm_mfd_add_devices(&i2c->dev, PLATFORM_DEVID_NONE, + act8945a_devs, ARRAY_SIZE(act8945a_devs), + NULL, 0, NULL); + if (ret) { + dev_err(&i2c->dev, "Failed to add sub devices\n"); + return ret; + } + + return 0; +} + +static const struct i2c_device_id act8945a_i2c_id[] = { + { "act8945a" }, + {} +}; +MODULE_DEVICE_TABLE(i2c, act8945a_i2c_id); + +static const struct of_device_id act8945a_of_match[] = { + { .compatible = "active-semi,act8945a", }, + {}, +}; +MODULE_DEVICE_TABLE(of, act8945a_of_match); + +static struct i2c_driver act8945a_i2c_driver = { + .driver = { + .name = "act8945a", + .of_match_table = act8945a_of_match, + }, + .probe = act8945a_i2c_probe, + .id_table = act8945a_i2c_id, +}; + +static int __init act8945a_i2c_init(void) +{ + return i2c_add_driver(&act8945a_i2c_driver); +} +subsys_initcall(act8945a_i2c_init); + +static void __exit act8945a_i2c_exit(void) +{ + i2c_del_driver(&act8945a_i2c_driver); +} +module_exit(act8945a_i2c_exit); + +MODULE_DESCRIPTION("ACT8945A PMIC multi-function driver"); +MODULE_AUTHOR("Wenyou Yang "); +MODULE_LICENSE("GPL"); -- cgit v1.3.1