FILTER_STACKTRACE
__generic_field(char *, stacktrace, FILTER_STACKTRACE);
__generic_field(char *, STACKTRACE, FILTER_STACKTRACE);
} else if (field->filter_type == FILTER_STACKTRACE) {
} else if (field && field->filter_type == FILTER_STACKTRACE) {
filter_type = is_stack ? FILTER_STACKTRACE : FILTER_OTHER;