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/hwmon/kbatt.c | 147 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 147 insertions(+) create mode 100644 drivers/hwmon/kbatt.c (limited to 'drivers/hwmon/kbatt.c') diff --git a/drivers/hwmon/kbatt.c b/drivers/hwmon/kbatt.c new file mode 100644 index 000000000..501b8f4de --- /dev/null +++ b/drivers/hwmon/kbatt.c @@ -0,0 +1,147 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2025 KEBA Industrial Automation GmbH + * + * Driver for KEBA battery monitoring controller FPGA IP core + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#define KBATT "kbatt" + +#define KBATT_CONTROL_REG 0x4 +#define KBATT_CONTROL_BAT_TEST 0x01 + +#define KBATT_STATUS_REG 0x8 +#define KBATT_STATUS_BAT_OK 0x01 + +#define KBATT_MAX_UPD_INTERVAL (10 * HZ) +#define KBATT_SETTLE_TIME_US (100 * USEC_PER_MSEC) + +struct kbatt { + /* update lock */ + struct mutex lock; + void __iomem *base; + + unsigned long next_update; /* in jiffies */ + bool alarm; +}; + +static bool kbatt_alarm(struct kbatt *kbatt) +{ + mutex_lock(&kbatt->lock); + + if (!kbatt->next_update || time_after(jiffies, kbatt->next_update)) { + /* switch load on */ + iowrite8(KBATT_CONTROL_BAT_TEST, + kbatt->base + KBATT_CONTROL_REG); + + /* wait some time to let things settle */ + fsleep(KBATT_SETTLE_TIME_US); + + /* check battery state */ + if (ioread8(kbatt->base + KBATT_STATUS_REG) & + KBATT_STATUS_BAT_OK) + kbatt->alarm = false; + else + kbatt->alarm = true; + + /* switch load off */ + iowrite8(0, kbatt->base + KBATT_CONTROL_REG); + + kbatt->next_update = jiffies + KBATT_MAX_UPD_INTERVAL; + } + + mutex_unlock(&kbatt->lock); + + return kbatt->alarm; +} + +static int kbatt_read(struct device *dev, enum hwmon_sensor_types type, + u32 attr, int channel, long *val) +{ + struct kbatt *kbatt = dev_get_drvdata(dev); + + *val = kbatt_alarm(kbatt) ? 1 : 0; + + return 0; +} + +static umode_t kbatt_is_visible(const void *data, enum hwmon_sensor_types type, + u32 attr, int channel) +{ + if (channel == 0 && attr == hwmon_in_min_alarm) + return 0444; + + return 0; +} + +static const struct hwmon_channel_info *kbatt_info[] = { + HWMON_CHANNEL_INFO(in, + /* 0: input minimum alarm channel */ + HWMON_I_MIN_ALARM), + NULL +}; + +static const struct hwmon_ops kbatt_hwmon_ops = { + .is_visible = kbatt_is_visible, + .read = kbatt_read, +}; + +static const struct hwmon_chip_info kbatt_chip_info = { + .ops = &kbatt_hwmon_ops, + .info = kbatt_info, +}; + +static int kbatt_probe(struct auxiliary_device *auxdev, + const struct auxiliary_device_id *id) +{ + struct keba_batt_auxdev *kbatt_auxdev = + container_of(auxdev, struct keba_batt_auxdev, auxdev); + struct device *dev = &auxdev->dev; + struct device *hwmon_dev; + struct kbatt *kbatt; + int retval; + + kbatt = devm_kzalloc(dev, sizeof(*kbatt), GFP_KERNEL); + if (!kbatt) + return -ENOMEM; + + retval = devm_mutex_init(dev, &kbatt->lock); + if (retval) + return retval; + + kbatt->base = devm_ioremap_resource(dev, &kbatt_auxdev->io); + if (IS_ERR(kbatt->base)) + return PTR_ERR(kbatt->base); + + hwmon_dev = devm_hwmon_device_register_with_info(dev, KBATT, kbatt, + &kbatt_chip_info, + NULL); + return PTR_ERR_OR_ZERO(hwmon_dev); +} + +static const struct auxiliary_device_id kbatt_devtype_aux[] = { + { .name = "keba.batt" }, + {} +}; +MODULE_DEVICE_TABLE(auxiliary, kbatt_devtype_aux); + +static struct auxiliary_driver kbatt_driver_aux = { + .name = KBATT, + .id_table = kbatt_devtype_aux, + .probe = kbatt_probe, +}; +module_auxiliary_driver(kbatt_driver_aux); + +MODULE_AUTHOR("Petar Bojanic "); +MODULE_AUTHOR("Gerhard Engleder "); +MODULE_DESCRIPTION("KEBA battery monitoring controller driver"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1