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HID: logitech-hidpp: Fix connect event race

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There is a connect event race in hidpp_probe() in these 2 lines:

	connected = hidpp_root_get_protocol_version(hidpp) == 0;
	atomic_set(&hidpp->connected, connected);

Specifically the following can happen:

1. This line from hidpp_probe() is executed:
	connected = hidpp_root_get_protocol_version(hidpp) == 0;
   and sets connected to false;

2. A connect-event packet is received and does:
	atomic_set(&hidpp->connected, true);

3. The next line from hidpp_probe() is executed:
	atomic_set(&hidpp->connected, connected);
   and sets the atomic_t back to 0 again.

4. hidpp_connect_event() runs and sees the connected device
   as disconnected because of this.

To fix this make hidpp_connect_event() query the connection status
of the device itself instead of having it rely on possibly stale
data cached in struct hidpp_device.

This series has been tested on the following devices:
Logitech Bluetooth Laser Travel Mouse (bluetooth, HID++ 1.0)
Logitech M720 Triathlon (bluetooth, HID++ 4.5)
Logitech M720 Triathlon (unifying, HID++ 4.5)
Logitech K400 Pro (unifying, HID++ 4.1)
Logitech K270 (eQUAD nano Lite, HID++ 2.0)
Logitech M185 (eQUAD nano Lite, HID++ 4.5)
Logitech LX501 keyboard (27 Mhz, HID++ builtin scroll-wheel, HID++ 1.0)
Logitech M-RAZ105 mouse (27 Mhz, HID++ extra mouse buttons, HID++ 1.0)

And by bentiss:
Logitech Touchpad T650 (unifying)
Logitech Touchpad T651 (bluetooth)
Logitech MX Master 3B (BLE)
Logitech G403 (plain USB / Gaming receiver)

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20231010102029.111003-11-hdegoede@redhat.com
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
This commit is contained in:
Hans de Goede 2023-10-10 12:20:27 +02:00 committed by Benjamin Tissoires
parent bb17b2c6dd
commit 680ee411a9
1 changed files with 5 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
drivers/hid/hid-logitech-hidpp.c
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@ -194,7 +194,6 @@ struct hidpp_device {
struct work_struct work;
struct kfifo delayed_work_fifo;
atomic_t connected;
struct input_dev *delayed_input;
unsigned long quirks;
@ -3893,8 +3892,6 @@ static int hidpp_raw_hidpp_event(struct hidpp_device *hidpp, u8 *data,
}
if (unlikely(hidpp_report_is_connect_event(hidpp, report))) {
atomic_set(&hidpp->connected,
!(report->rap.params[0] & (1 << 6)));
if (schedule_work(&hidpp->work) == 0)
dbg_hid("%s: connect event already queued\n", __func__);
return 1;
@ -4189,12 +4186,14 @@ static struct input_dev *hidpp_allocate_input(struct hid_device *hdev)
static void hidpp_connect_event(struct hidpp_device *hidpp)
{
struct hid_device *hdev = hidpp->hid_dev;
int ret = 0;
bool connected = atomic_read(&hidpp->connected);
struct input_dev *input;
char *name, *devm_name;
int ret;
if (!connected) {
/* Get device version to check if it is connected */
ret = hidpp_root_get_protocol_version(hidpp);
if (ret) {
hid_info(hidpp->hid_dev, "Disconnected\n");
if (hidpp->battery.ps) {
hidpp->battery.online = false;
hidpp->battery.status = POWER_SUPPLY_STATUS_UNKNOWN;
@ -4236,16 +4235,6 @@ static void hidpp_connect_event(struct hidpp_device *hidpp)
return;
}
/* the device is already connected, we can ask for its name and
* protocol */
if (!hidpp->protocol_major) {
ret = hidpp_root_get_protocol_version(hidpp);
if (ret) {
hid_err(hdev, "Can not get the protocol version.\n");
return;
}
}
if (hidpp->protocol_major >= 2) {
u8 feature_index;
@ -4395,7 +4384,6 @@ static int hidpp_probe(struct hid_device *hdev, const struct hid_device_id *id)
{
struct hidpp_device *hidpp;
int ret;
bool connected;
unsigned int connect_mask = HID_CONNECT_DEFAULT;
/* report_fixup needs drvdata to be set before we call hid_parse */
@ -4485,9 +4473,6 @@ static int hidpp_probe(struct hid_device *hdev, const struct hid_device_id *id)
else
hidpp_non_unifying_init(hidpp);
connected = hidpp_root_get_protocol_version(hidpp) == 0;
atomic_set(&hidpp->connected, connected);
schedule_work(&hidpp->work);
flush_work(&hidpp->work);