Currently, SimulateCrash.copy_file (buildscripts/resmokelib/testing/hooks/simulate_crash.py) stats a file once, then copies it via a sendfile loop up to that stat'd size. If the file shrinks between the stat and the end of the copy - e.g. a background WT thread hadn't fully parked when the node was paused - sendfile returns 0 early and the hook raised unconditionally, aborting the whole test run over what is only a best-effort diagnostic dbpath snapshot. Update SimulateCrash.copy_file to re-check the file's size on a premature EOF; if the file grew, it continues copying; if it shrank, it logs a warning and keeps the bytes copied instead of raising.