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-vrc2.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 91 insertions(+) create mode 100644 drivers/hid/hid-vrc2.c (limited to 'drivers/hid/hid-vrc2.c') diff --git a/drivers/hid/hid-vrc2.c b/drivers/hid/hid-vrc2.c new file mode 100644 index 000000000..7dc41e92f --- /dev/null +++ b/drivers/hid/hid-vrc2.c @@ -0,0 +1,91 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * HID driver for VRC-2 2-axis Car controller + * + * Copyright (C) 2022 Marcus Folkesson + */ + +#include +#include +#include + +/* + * VID/PID are probably "borrowed", so keep them locally and + * do not populate hid-ids.h with those. + */ +#define USB_VENDOR_ID_VRC2 (0x07c0) +#define USB_DEVICE_ID_VRC2 (0x1125) + +static const __u8 vrc2_rdesc_fixed[] = { + 0x05, 0x01, // Usage Page (Generic Desktop Ctrls) + 0x09, 0x04, // Usage (Joystick) + 0xA1, 0x01, // Collection (Application) + 0x09, 0x01, // Usage (Pointer) + 0xA1, 0x00, // Collection (Physical) + 0x09, 0x30, // Usage (X) + 0x09, 0x31, // Usage (Y) + 0x15, 0x00, // Logical Minimum (0) + 0x26, 0xFF, 0x07, // Logical Maximum (2047) + 0x35, 0x00, // Physical Minimum (0) + 0x46, 0xFF, 0x00, // Physical Maximum (255) + 0x75, 0x10, // Report Size (16) + 0x95, 0x02, // Report Count (2) + 0x81, 0x02, // Input (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position) + 0xC0, // End Collection + 0x75, 0x08, // Report Size (8) + 0x95, 0x03, // Report Count (3) + 0x81, 0x03, // Input (Cnst,Var,Abs) + 0xC0, // End Collection +}; + +static const __u8 *vrc2_report_fixup(struct hid_device *hdev, __u8 *rdesc, + unsigned int *rsize) +{ + hid_info(hdev, "fixing up VRC-2 report descriptor\n"); + *rsize = sizeof(vrc2_rdesc_fixed); + return vrc2_rdesc_fixed; +} + +static int vrc2_probe(struct hid_device *hdev, const struct hid_device_id *id) +{ + int ret; + + /* + * The device gives us 2 separate USB endpoints. + * One of those (the one with report descriptor size of 23) is just bogus so ignore it + */ + if (hdev->dev_rsize == 23) + return -ENODEV; + + ret = hid_parse(hdev); + if (ret) { + hid_err(hdev, "parse failed\n"); + return ret; + } + + ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT); + if (ret) { + hid_err(hdev, "hw start failed\n"); + return ret; + } + + return 0; +} + +static const struct hid_device_id vrc2_devices[] = { + { HID_USB_DEVICE(USB_VENDOR_ID_VRC2, USB_DEVICE_ID_VRC2) }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(hid, vrc2_devices); + +static struct hid_driver vrc2_driver = { + .name = "vrc2", + .id_table = vrc2_devices, + .report_fixup = vrc2_report_fixup, + .probe = vrc2_probe, +}; +module_hid_driver(vrc2_driver); + +MODULE_AUTHOR("Marcus Folkesson "); +MODULE_DESCRIPTION("HID driver for VRC-2 2-axis Car controller"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1