Bluetooth: Fix reference counting for LE-scan based connections
The code should never directly call hci_conn_hash_del since many
cleanup & reference counting updates would be lost. Normally
hci_conn_del is the right thing to do, but in the case of a connection
doing LE scanning this could cause a deadlock due to doing a
cancel_delayed_work_sync() on the same work callback that we were
called from.
Connections in the LE scanning state actually need very little cleanup
- just a small subset of hci_conn_del. To solve the issue, refactor
out these essential pieces into a new hci_conn_cleanup() function and
call that from the two necessary places.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index 2ebcaaa..4c240c1 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -99,12 +99,41 @@
}
}
+static void hci_conn_cleanup(struct hci_conn *conn)
+{
+ struct hci_dev *hdev = conn->hdev;
+
+ if (test_bit(HCI_CONN_PARAM_REMOVAL_PEND, &conn->flags))
+ hci_conn_params_del(conn->hdev, &conn->dst, conn->dst_type);
+
+ hci_chan_list_flush(conn);
+
+ hci_conn_hash_del(hdev, conn);
+
+ if (hdev->notify)
+ hdev->notify(hdev, HCI_NOTIFY_CONN_DEL);
+
+ hci_conn_del_sysfs(conn);
+
+ debugfs_remove_recursive(conn->debugfs);
+
+ hci_dev_put(hdev);
+
+ hci_conn_put(conn);
+}
+
/* This function requires the caller holds hdev->lock */
static void hci_connect_le_scan_remove(struct hci_conn *conn)
{
hci_connect_le_scan_cleanup(conn);
- hci_conn_hash_del(conn->hdev, conn);
+ /* We can't call hci_conn_del here since that would deadlock
+ * with trying to call cancel_delayed_work_sync(&conn->disc_work).
+ * Instead, call just hci_conn_cleanup() which contains the bare
+ * minimum cleanup operations needed for a connection in this
+ * state.
+ */
+ hci_conn_cleanup(conn);
}
static void hci_acl_create_connection(struct hci_conn *conn)
@@ -582,27 +611,17 @@
}
}
- hci_chan_list_flush(conn);
-
if (conn->amp_mgr)
amp_mgr_put(conn->amp_mgr);
- hci_conn_hash_del(hdev, conn);
- if (hdev->notify)
- hdev->notify(hdev, HCI_NOTIFY_CONN_DEL);
-
skb_queue_purge(&conn->data_q);
- hci_conn_del_sysfs(conn);
-
- debugfs_remove_recursive(conn->debugfs);
-
- if (test_bit(HCI_CONN_PARAM_REMOVAL_PEND, &conn->flags))
- hci_conn_params_del(conn->hdev, &conn->dst, conn->dst_type);
-
- hci_dev_put(hdev);
-
- hci_conn_put(conn);
+ /* Remove the connection from the list and cleanup its remaining
+ * state. This is a separate function since for some cases like
+ * BT_CONNECT_SCAN we *only* want the cleanup part without the
+ * rest of hci_conn_del.
+ */
+ hci_conn_cleanup(conn);
return 0;
}