From 2c179ece3bfbb5a0d80431281a4c2a1019081f10 Mon Sep 17 00:00:00 2001 From: Rodrigo Rivas Costa Date: Tue, 16 Jun 2020 18:44:18 +0200 Subject: [PATCH] HID: steam: fixes race in handling device list. [ Upstream commit 2d3f53a80e4eed078669853a178ed96d88f74143 ] 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 Tested-by: Siarhei Vishniakou Signed-off-by: Jiri Kosina Signed-off-by: Sasha Levin --- 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)) {