[STABLE v5.15-v5.10 6/6] HID: steam: Clean up locking
From: Lee Jones
Date: Tue Oct 13 2026 - 05:27:32 EST
From: Vicki Pfau <vi@xxxxxxxxxxx>
[ Upstream commit de1d341b9b3ec9655f31fb8b44f784cca5e670ad ]
This cleans up several issues with locking behavior, including RCU accesses
not being guarded behind a lock.
Signed-off-by: Vicki Pfau <vi@xxxxxxxxxxx>
Signed-off-by: Jiri Kosina <jkosina@xxxxxxxx>
[Lee: Use explicit lock/unlock calls instead of guard(), adapt to
steam->mutex, and omit Steam Deck sensors, mode_switch,
rumble_work, coalesce_rumble_work and Ibex changes as
691ead124a0c, e133dc99fc07, a0fbd9437d7d, 1d4549fd1115,
fcfa7db89f7a and 0a80b4e8ec6a are not present]
Signed-off-by: Lee Jones <lee@xxxxxxxxxx>
---
drivers/hid/hid-steam.c | 61 +++++++++++++++++++++++++++--------------
1 file changed, 41 insertions(+), 20 deletions(-)
diff --git a/drivers/hid/hid-steam.c b/drivers/hid/hid-steam.c
index 544d45f3fc6b..4ba922d750df 100644
--- a/drivers/hid/hid-steam.c
+++ b/drivers/hid/hid-steam.c
@@ -114,6 +114,7 @@ struct steam_device {
spinlock_t lock;
struct hid_device *hdev, *client_hdev;
struct mutex mutex;
+ struct mutex registration_mutex;
unsigned long client_opened;
struct input_dev __rcu *input;
unsigned long quirks;
@@ -294,9 +295,14 @@ static void steam_set_lizard_mode(struct steam_device *steam, bool enable)
static int steam_input_open(struct input_dev *dev)
{
struct steam_device *steam = input_get_drvdata(dev);
+ unsigned long flags;
+ bool client_opened;
+ spin_lock_irqsave(&steam->lock, flags);
+ client_opened = steam->client_opened;
+ spin_unlock_irqrestore(&steam->lock, flags);
mutex_lock(&steam->mutex);
- if (!steam->client_opened && lizard_mode)
+ if (!client_opened && lizard_mode)
steam_set_lizard_mode(steam, false);
mutex_unlock(&steam->mutex);
return 0;
@@ -305,9 +311,14 @@ static int steam_input_open(struct input_dev *dev)
static void steam_input_close(struct input_dev *dev)
{
struct steam_device *steam = input_get_drvdata(dev);
+ unsigned long flags;
+ bool client_opened;
+ spin_lock_irqsave(&steam->lock, flags);
+ client_opened = steam->client_opened;
+ spin_unlock_irqrestore(&steam->lock, flags);
mutex_lock(&steam->mutex);
- if (!steam->client_opened && lizard_mode)
+ if (!client_opened && lizard_mode)
steam_set_lizard_mode(steam, true);
mutex_unlock(&steam->mutex);
}
@@ -513,40 +524,43 @@ static int steam_register(struct steam_device *steam)
{
int ret;
+ mutex_lock(&steam->registration_mutex);
/*
* This function can be called several times in a row with the
* wireless adaptor, without steam_unregister() between them, because
* another client send a get_connection_status command, for example.
* The battery and serial number are set just once per device.
*/
- if (steam->registered)
+ if (steam->registered) {
+ mutex_unlock(&steam->registration_mutex);
return 0;
+ }
+ mutex_lock(&steam->mutex);
/*
* Unlikely, but getting the serial could fail, and it is not so
* important, so make up a serial number and go on.
*/
- mutex_lock(&steam->mutex);
if (steam_get_serial(steam) < 0 || !steam->serial_no[0])
strlcpy(steam->serial_no, "XXXXXXXXXX",
sizeof(steam->serial_no));
- mutex_unlock(&steam->mutex);
hid_info(steam->hdev, "Steam Controller '%s' connected",
steam->serial_no);
+ steam_set_lizard_mode(steam, lizard_mode);
+ mutex_unlock(&steam->mutex);
+
/* ignore battery errors, we can live without it */
if (steam->quirks & STEAM_QUIRK_WIRELESS)
steam_battery_register(steam);
- mutex_lock(&steam->mutex);
- steam_set_lizard_mode(steam, lizard_mode);
- mutex_unlock(&steam->mutex);
ret = steam_input_register(steam);
if (ret != 0)
goto steam_register_input_fail;
steam->registered = true;
+ mutex_unlock(&steam->registration_mutex);
mutex_lock(&steam_devices_lock);
if (list_empty(&steam->list))
list_add(&steam->list, &steam_devices);
@@ -555,6 +569,7 @@ static int steam_register(struct steam_device *steam)
steam_register_input_fail:
steam_battery_unregister(steam);
+ mutex_unlock(&steam->registration_mutex);
return ret;
}
@@ -565,9 +580,11 @@ static void steam_unregister(struct steam_device *steam)
hid_info(steam->hdev, "Steam Controller '%s' disconnected",
steam->serial_no);
+ mutex_lock(&steam->registration_mutex);
steam->registered = false;
steam_battery_unregister(steam);
steam_input_unregister(steam);
+ mutex_unlock(&steam->registration_mutex);
mutex_lock(&steam_devices_lock);
list_del_init(&steam->list);
mutex_unlock(&steam_devices_lock);
@@ -745,6 +762,7 @@ static int steam_probe(struct hid_device *hdev,
hid_set_drvdata(hdev, steam);
spin_lock_init(&steam->lock);
mutex_init(&steam->mutex);
+ mutex_init(&steam->registration_mutex);
steam->quirks = id->driver_data;
INIT_WORK(&steam->work_connect, steam_work_connect_cb);
INIT_LIST_HEAD(&steam->list);
@@ -835,13 +853,10 @@ static void steam_remove(struct hid_device *hdev)
static void steam_do_connect_event(struct steam_device *steam, bool connected)
{
- unsigned long flags;
bool changed;
- spin_lock_irqsave(&steam->lock, flags);
changed = steam->connected != connected;
steam->connected = connected;
- spin_unlock_irqrestore(&steam->lock, flags);
if (changed && schedule_work(&steam->work_connect) == 0)
dbg_hid("%s: connected=%d event already queued\n",
@@ -1008,8 +1023,6 @@ static void steam_do_input_event(struct steam_device *steam,
static void steam_do_battery_event(struct steam_device *steam,
struct power_supply *battery, u8 *data)
{
- unsigned long flags;
-
s16 volts = steam_le16(data + 12);
u8 batt = data[14];
@@ -1017,10 +1030,8 @@ static void steam_do_battery_event(struct steam_device *steam,
rcu_read_lock();
battery = rcu_dereference(steam->battery);
if (likely(battery)) {
- spin_lock_irqsave(&steam->lock, flags);
steam->voltage = volts;
steam->battery_charge = batt;
- spin_unlock_irqrestore(&steam->lock, flags);
power_supply_changed(battery);
}
rcu_read_unlock();
@@ -1033,10 +1044,12 @@ static int steam_raw_event(struct hid_device *hdev,
struct steam_device *steam = hid_get_drvdata(hdev);
struct input_dev *input;
struct power_supply *battery;
+ unsigned long flags;
if (!steam)
return 0;
+ spin_lock_irqsave(&steam->lock, flags);
if (steam->client_opened)
hid_input_report(steam->client_hdev, HID_FEATURE_REPORT,
data, size, 0);
@@ -1057,12 +1070,12 @@ static int steam_raw_event(struct hid_device *hdev,
*/
if (size != 64 || data[0] != 1 || data[1] != 0)
- return 0;
+ goto out;
switch (data[2]) {
case STEAM_EV_INPUT_DATA:
if (steam->client_opened)
- return 0;
+ goto out;
rcu_read_lock();
input = rcu_dereference(steam->input);
if (likely(input))
@@ -1100,6 +1113,8 @@ static int steam_raw_event(struct hid_device *hdev,
}
break;
}
+out:
+ spin_unlock_irqrestore(&steam->lock, flags);
return 0;
}
@@ -1108,6 +1123,8 @@ static int steam_param_set_lizard_mode(const char *val,
{
struct steam_device *steam;
int ret;
+ bool client_opened;
+ unsigned long flags;
ret = param_set_bool(val, kp);
if (ret)
@@ -1115,10 +1132,14 @@ static int steam_param_set_lizard_mode(const char *val,
mutex_lock(&steam_devices_lock);
list_for_each_entry(steam, &steam_devices, list) {
- mutex_lock(&steam->mutex);
- if (!steam->client_opened)
+ spin_lock_irqsave(&steam->lock, flags);
+ client_opened = steam->client_opened;
+ spin_unlock_irqrestore(&steam->lock, flags);
+ if (!client_opened) {
+ mutex_lock(&steam->mutex);
steam_set_lizard_mode(steam, lizard_mode);
- mutex_unlock(&steam->mutex);
+ mutex_unlock(&steam->mutex);
+ }
}
mutex_unlock(&steam_devices_lock);
return 0;
--
2.56.0.385.gd3acb90ef8-goog