Detect when sbws stalls and log backtrace
Since it's possible that there will be other bug we haven't found yet, detect when sbws is stalling. Also print backtrace so that operators can open tickets with the backtrace and help to find the bug.
Since it's possible that there will be other bug we haven't found yet, detect when sbws is stalling. Also print backtrace so that operators can open tickets with the backtrace and help to find the bug.