Do not call Qt from non-Qt threads, this will segfault (give_error)

plugins/trezor.py

@@ -7,15 +7,16 @@ from time import sleep
 from base64 import b64encode, b64decode
 
 import electrum
-from electrum_gui.qt.password_dialog import make_password_dialog, run_password_dialog
-from electrum_gui.qt.util import ok_cancel_buttons, EnterButton
 from electrum.account import BIP32_Account
 from electrum.bitcoin import EncodeBase58Check, public_key_to_bc_address, bc_address_to_hash_160
 from electrum.i18n import _
 from electrum.plugins import BasePlugin, hook
 from electrum.transaction import deserialize
 from electrum.wallet import NewWallet
+from electrum.util import print_error
 
+from electrum_gui.qt.password_dialog import make_password_dialog, run_password_dialog
+from electrum_gui.qt.util import ok_cancel_buttons, EnterButton
 
 try:
     from trezorlib.client import types
@@ -32,7 +33,7 @@ def log(msg):
     stderr.flush()
 
 def give_error(message):
-    QMessageBox.warning(QDialog(), _('Warning'), _(message), _('OK'))
+    print_error(message)
     raise Exception(message)
 
 class Plugin(BasePlugin):