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/input/touchscreen/ipaq-micro-ts.c | 156 ++++++++++++++++++++++++++++++ 1 file changed, 156 insertions(+) create mode 100644 drivers/input/touchscreen/ipaq-micro-ts.c (limited to 'drivers/input/touchscreen/ipaq-micro-ts.c') diff --git a/drivers/input/touchscreen/ipaq-micro-ts.c b/drivers/input/touchscreen/ipaq-micro-ts.c new file mode 100644 index 000000000..243e6465d --- /dev/null +++ b/drivers/input/touchscreen/ipaq-micro-ts.c @@ -0,0 +1,156 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * + * h3600 atmel micro companion support, touchscreen subdevice + * Author : Alessandro Gardich + * Author : Dmitry Artamonow + * Author : Linus Walleij + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +struct touchscreen_data { + struct input_dev *input; + struct ipaq_micro *micro; +}; + +static void micro_ts_receive(void *data, int len, unsigned char *msg) +{ + struct touchscreen_data *ts = data; + + if (len == 4) { + input_report_abs(ts->input, ABS_X, + be16_to_cpup((__be16 *) &msg[2])); + input_report_abs(ts->input, ABS_Y, + be16_to_cpup((__be16 *) &msg[0])); + input_report_key(ts->input, BTN_TOUCH, 1); + input_sync(ts->input); + } else if (len == 0) { + input_report_abs(ts->input, ABS_X, 0); + input_report_abs(ts->input, ABS_Y, 0); + input_report_key(ts->input, BTN_TOUCH, 0); + input_sync(ts->input); + } +} + +static void micro_ts_toggle_receive(struct touchscreen_data *ts, bool enable) +{ + struct ipaq_micro *micro = ts->micro; + + guard(spinlock_irq)(µ->lock); + + if (enable) { + micro->ts = micro_ts_receive; + micro->ts_data = ts; + } else { + micro->ts = NULL; + micro->ts_data = NULL; + } +} + +static int micro_ts_open(struct input_dev *input) +{ + struct touchscreen_data *ts = input_get_drvdata(input); + + micro_ts_toggle_receive(ts, true); + + return 0; +} + +static void micro_ts_close(struct input_dev *input) +{ + struct touchscreen_data *ts = input_get_drvdata(input); + + micro_ts_toggle_receive(ts, false); +} + +static int micro_ts_probe(struct platform_device *pdev) +{ + struct ipaq_micro *micro = dev_get_drvdata(pdev->dev.parent); + struct touchscreen_data *ts; + int error; + + ts = devm_kzalloc(&pdev->dev, sizeof(*ts), GFP_KERNEL); + if (!ts) + return -ENOMEM; + + ts->micro = micro; + + ts->input = devm_input_allocate_device(&pdev->dev); + if (!ts->input) { + dev_err(&pdev->dev, "failed to allocate input device\n"); + return -ENOMEM; + } + + ts->input->name = "ipaq micro ts"; + ts->input->open = micro_ts_open; + ts->input->close = micro_ts_close; + + input_set_drvdata(ts->input, ts); + + input_set_capability(ts->input, EV_KEY, BTN_TOUCH); + input_set_capability(ts->input, EV_ABS, ABS_X); + input_set_capability(ts->input, EV_ABS, ABS_Y); + input_set_abs_params(ts->input, ABS_X, 0, 1023, 0, 0); + input_set_abs_params(ts->input, ABS_Y, 0, 1023, 0, 0); + + error = input_register_device(ts->input); + if (error) { + dev_err(&pdev->dev, "error registering touch input\n"); + return error; + } + + platform_set_drvdata(pdev, ts); + + dev_info(&pdev->dev, "iPAQ micro touchscreen\n"); + + return 0; +} + +static int micro_ts_suspend(struct device *dev) +{ + struct touchscreen_data *ts = dev_get_drvdata(dev); + + micro_ts_toggle_receive(ts, false); + + return 0; +} + +static int micro_ts_resume(struct device *dev) +{ + struct touchscreen_data *ts = dev_get_drvdata(dev); + struct input_dev *input = ts->input; + + guard(mutex)(&input->mutex); + + if (input_device_enabled(input)) + micro_ts_toggle_receive(ts, true); + + return 0; +} + +static DEFINE_SIMPLE_DEV_PM_OPS(micro_ts_dev_pm_ops, + micro_ts_suspend, micro_ts_resume); + +static struct platform_driver micro_ts_device_driver = { + .driver = { + .name = "ipaq-micro-ts", + .pm = pm_sleep_ptr(µ_ts_dev_pm_ops), + }, + .probe = micro_ts_probe, +}; +module_platform_driver(micro_ts_device_driver); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("driver for iPAQ Atmel micro touchscreen"); +MODULE_ALIAS("platform:ipaq-micro-ts"); -- cgit v1.3.1