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/hid/hid-google-stadiaff.c | 133 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 133 insertions(+) create mode 100644 drivers/hid/hid-google-stadiaff.c (limited to 'drivers/hid/hid-google-stadiaff.c') diff --git a/drivers/hid/hid-google-stadiaff.c b/drivers/hid/hid-google-stadiaff.c new file mode 100644 index 000000000..0214aae6b --- /dev/null +++ b/drivers/hid/hid-google-stadiaff.c @@ -0,0 +1,133 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Stadia controller rumble support. + * + * Copyright 2023 Google LLC + */ + +#include +#include +#include +#include + +#include "hid-ids.h" + +#define STADIA_FF_REPORT_ID 5 + +struct stadiaff_device { + struct hid_device *hid; + struct hid_report *report; + u32 magnitudes; + struct work_struct work; +}; + +static void stadiaff_work(struct work_struct *work) +{ + struct stadiaff_device *stadiaff = + container_of(work, struct stadiaff_device, work); + struct hid_field *rumble_field = stadiaff->report->field[0]; + u32 mags = READ_ONCE(stadiaff->magnitudes); + + rumble_field->value[0] = mags & 0xffff; + rumble_field->value[1] = (mags >> 16) & 0xffff; + + hid_hw_request(stadiaff->hid, stadiaff->report, HID_REQ_SET_REPORT); +} + +static int stadiaff_play(struct input_dev *dev, void *data, + struct ff_effect *effect) +{ + struct hid_device *hid = input_get_drvdata(dev); + struct stadiaff_device *stadiaff = hid_get_drvdata(hid); + u32 mags = (u32)effect->u.rumble.strong_magnitude | + ((u32)effect->u.rumble.weak_magnitude << 16); + + WRITE_ONCE(stadiaff->magnitudes, mags); + schedule_work(&stadiaff->work); + + return 0; +} + +static int stadia_input_open(struct input_dev *dev) +{ + struct hid_device *hid = input_get_drvdata(dev); + struct stadiaff_device *stadiaff = hid_get_drvdata(hid); + int error; + + error = hid_hw_open(hid); + if (error) + return error; + + enable_work(&stadiaff->work); + return 0; +} + +static void stadia_input_close(struct input_dev *dev) +{ + struct hid_device *hid = input_get_drvdata(dev); + struct stadiaff_device *stadiaff = hid_get_drvdata(hid); + + WRITE_ONCE(stadiaff->magnitudes, 0); + stadiaff_work(&stadiaff->work); + disable_work_sync(&stadiaff->work); + + hid_hw_close(hid); +} + +static int stadia_input_configured(struct hid_device *hid, struct hid_input *hidinput) +{ + struct stadiaff_device *stadiaff; + struct hid_report *report; + struct input_dev *dev = hidinput->input; + int error; + + if (!list_is_first(&hidinput->list, &hid->inputs)) + return 0; + + report = hid_validate_values(hid, HID_OUTPUT_REPORT, + STADIA_FF_REPORT_ID, 0, 2); + if (!report) + return -ENODEV; + + stadiaff = devm_kzalloc(&hid->dev, sizeof(struct stadiaff_device), + GFP_KERNEL); + if (!stadiaff) + return -ENOMEM; + + hid_set_drvdata(hid, stadiaff); + + input_set_capability(dev, EV_FF, FF_RUMBLE); + + error = input_ff_create_memless(dev, NULL, stadiaff_play); + if (error) + return error; + + stadiaff->hid = hid; + stadiaff->report = report; + INIT_WORK(&stadiaff->work, stadiaff_work); + disable_work_sync(&stadiaff->work); + + dev->open = stadia_input_open; + dev->close = stadia_input_close; + + hid_info(hid, "Force Feedback for Google Stadia controller\n"); + + return 0; +} + +static const struct hid_device_id stadia_devices[] = { + { HID_USB_DEVICE(USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_STADIA) }, + { HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_STADIA) }, + { } +}; +MODULE_DEVICE_TABLE(hid, stadia_devices); + +static struct hid_driver stadia_driver = { + .name = "stadia", + .id_table = stadia_devices, + .input_configured = stadia_input_configured, +}; +module_hid_driver(stadia_driver); + +MODULE_DESCRIPTION("Google Stadia controller rumble support."); +MODULE_LICENSE("GPL"); -- cgit v1.3.1