[PATCH] HID: steam: fixes race in handling device list.
From: Rodrigo Rivas Costa <hidden>
Date: 2020-06-16 16:45:10
Subsystem:
hid core layer, the rest · Maintainers:
Jiri Kosina, Benjamin Tissoires, Linus Torvalds
Using uhid and KASAN this driver crashed because it was getting several connection events where it only expected one. Then the device was added several times to the static device list and it got corrupted. This patch checks if the device is already in the list before adding it. Signed-off-by: Rodrigo Rivas Costa <redacted> Tested-by: Siarhei Vishniakou <redacted> --- drivers/hid/hid-steam.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/hid/hid-steam.c b/drivers/hid/hid-steam.c
index 6286204d4c56..a3b151b29bd7 100644
--- a/drivers/hid/hid-steam.c
+++ b/drivers/hid/hid-steam.c@@ -526,7 +526,8 @@ static int steam_register(struct steam_device *steam) steam_battery_register(steam); mutex_lock(&steam_devices_lock); - list_add(&steam->list, &steam_devices); + if (list_empty(&steam->list)) + list_add(&steam->list, &steam_devices); mutex_unlock(&steam_devices_lock); }
@@ -552,7 +553,7 @@ static void steam_unregister(struct steam_device *steam) hid_info(steam->hdev, "Steam Controller '%s' disconnected", steam->serial_no); mutex_lock(&steam_devices_lock); - list_del(&steam->list); + list_del_init(&steam->list); mutex_unlock(&steam_devices_lock); steam->serial_no[0] = 0; }
@@ -738,6 +739,7 @@ static int steam_probe(struct hid_device *hdev, mutex_init(&steam->mutex); steam->quirks = id->driver_data; INIT_WORK(&steam->work_connect, steam_work_connect_cb); + INIT_LIST_HEAD(&steam->list); steam->client_hdev = steam_create_client_hid(hdev); if (IS_ERR(steam->client_hdev)) {
--
2.27.0