From f161dd4122ffa73e4e12000309dca65bec80d416 Mon Sep 17 00:00:00 2001 From: Johan Hedberg Date: Fri, 15 Aug 2014 21:06:54 +0300 Subject: [PATCH] Bluetooth: Fix hci_conn reference counting for auto-connections Recently the LE passive scanning and auto-connections feature was introduced. It uses the hci_connect_le() API which returns a hci_conn along with a reference count to that object. All previous users would tie this returned reference to some existing object, such as an L2CAP channel, and there'd be no leaked references this way. For auto-connections however the reference was returned but not stored anywhere, leaving established connections with one higher reference count than they should have. Instead of playing special tricks with hci_conn_hold/drop this patch associates the returned reference from hci_connect_le() with the object that in practice does own this reference, i.e. the hci_conn_params struct that caused us to initiate a connection in the first place. Once the connection is established or fails to establish this reference is removed appropriately. One extra thing needed is to call hci_pend_le_actions_clear() before calling hci_conn_hash_flush() so that the reference is cleared before the hci_conn objects are fully removed. Signed-off-by: Johan Hedberg Signed-off-by: Marcel Holtmann --- include/net/bluetooth/hci_core.h | 2 ++ net/bluetooth/hci_conn.c | 8 ++++++++ net/bluetooth/hci_core.c | 14 ++++++++++++-- net/bluetooth/hci_event.c | 17 +++++++++++++++-- 4 files changed, 37 insertions(+), 4 deletions(-) diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h index b5d5af3aa469..6f884e6c731e 100644 --- a/include/net/bluetooth/hci_core.h +++ b/include/net/bluetooth/hci_core.h @@ -464,6 +464,8 @@ struct hci_conn_params { HCI_AUTO_CONN_ALWAYS, HCI_AUTO_CONN_LINK_LOSS, } auto_connect; + + struct hci_conn *conn; }; extern struct list_head hci_dev_list; diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c index b50dabb3f86a..faff6247ac8f 100644 --- a/net/bluetooth/hci_conn.c +++ b/net/bluetooth/hci_conn.c @@ -589,6 +589,14 @@ EXPORT_SYMBOL(hci_get_route); void hci_le_conn_failed(struct hci_conn *conn, u8 status) { struct hci_dev *hdev = conn->hdev; + struct hci_conn_params *params; + + params = hci_pend_le_action_lookup(&hdev->pend_le_conns, &conn->dst, + conn->dst_type); + if (params && params->conn) { + hci_conn_drop(params->conn); + params->conn = NULL; + } conn->state = BT_CLOSED; diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index c32d361c0cf7..1d9c29a00568 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -2536,8 +2536,13 @@ static void hci_pend_le_actions_clear(struct hci_dev *hdev) { struct hci_conn_params *p; - list_for_each_entry(p, &hdev->le_conn_params, list) + list_for_each_entry(p, &hdev->le_conn_params, list) { + if (p->conn) { + hci_conn_drop(p->conn); + p->conn = NULL; + } list_del_init(&p->action); + } BT_DBG("All LE pending actions cleared"); } @@ -2578,8 +2583,8 @@ static int hci_dev_do_close(struct hci_dev *hdev) hci_dev_lock(hdev); hci_inquiry_cache_flush(hdev); - hci_conn_hash_flush(hdev); hci_pend_le_actions_clear(hdev); + hci_conn_hash_flush(hdev); hci_dev_unlock(hdev); hci_notify(hdev, HCI_DEV_DOWN); @@ -3727,6 +3732,9 @@ void hci_conn_params_del(struct hci_dev *hdev, bdaddr_t *addr, u8 addr_type) if (!params) return; + if (params->conn) + hci_conn_drop(params->conn); + list_del(¶ms->action); list_del(¶ms->list); kfree(params); @@ -3757,6 +3765,8 @@ void hci_conn_params_clear_all(struct hci_dev *hdev) struct hci_conn_params *params, *tmp; list_for_each_entry_safe(params, tmp, &hdev->le_conn_params, list) { + if (params->conn) + hci_conn_drop(params->conn); list_del(¶ms->action); list_del(¶ms->list); kfree(params); diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index be35598984d9..a6000823f0ff 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -4221,8 +4221,13 @@ static void hci_le_conn_complete_evt(struct hci_dev *hdev, struct sk_buff *skb) hci_proto_connect_cfm(conn, ev->status); params = hci_conn_params_lookup(hdev, &conn->dst, conn->dst_type); - if (params) + if (params) { list_del_init(¶ms->action); + if (params->conn) { + hci_conn_drop(params->conn); + params->conn = NULL; + } + } unlock: hci_update_background_scan(hdev); @@ -4304,8 +4309,16 @@ static void check_pending_le_conn(struct hci_dev *hdev, bdaddr_t *addr, conn = hci_connect_le(hdev, addr, addr_type, BT_SECURITY_LOW, HCI_LE_AUTOCONN_TIMEOUT, HCI_ROLE_MASTER); - if (!IS_ERR(conn)) + if (!IS_ERR(conn)) { + /* Store the pointer since we don't really have any + * other owner of the object besides the params that + * triggered it. This way we can abort the connection if + * the parameters get removed and keep the reference + * count consistent once the connection is established. + */ + params->conn = conn; return; + } switch (PTR_ERR(conn)) { case -EBUSY: -- 2.20.1