Created attachment 73842 [details]
Output from successive runs of 'top'
Running 'top' revealed the memory leak.
This attachment is (clipped) output from top. Running the 'prboom-plus' game
on a kernel that was not leaking, then several snapshots on a kernel that was
leaking.
Eventually the game was taken out by the OOM killer, and system memory usage
was restored to normal.