gnome-shell installs this log handler from main.c:

static void
default_log_handler (const char     *log_domain,
                     GLogLevelFlags  log_level,
                     const char     *message,
                     gpointer        data)
{
  TpDebugSender *sender = data;
  GTimeVal now;

  g_get_current_time (&now);

  tp_debug_sender_add_message (sender, &now, log_domain, log_level, message);

  /* Filter out telepathy-glib logs, we don't want to flood Shell's output
   * with those. */
  if (!g_str_has_prefix (log_domain, "tp-glib"))
    g_log_default_handler (log_domain, log_level, message, data);
}


The problem is that log_domain can be NULL and g_str_has_prefix() requires a non-NULL first argument.  This causes g_str_has_prefix() to throw a g_return_if_fail() message which causes re-entry into the logging code, leading to an abort.