In outOfSpace() on line 1273 of mongo/db/pdfile.cpp, the log() line reporting a failure to find space for a document after allocating a new extent to hold it is missing an endl at the end of the line. This will prevent the line from being logged until another line logged from this thread includes an endl. This just makes the logged output badly formatted, because the code will retry 10 times and each retry logs its output with an endl. Because of the missing endl, the first of these appears bare on the next log line (no timestamp or thread name).