$ ./t -k 100000 -W 10
t: process 54528
    1: 10 workers, 3 tables
...
Finished verifying a checkpoint with 3 tables and 29114 keys
t, file:__wt0000.wt, session.checkpoint: ../src/btree/rec_write.c, 3128: state == WT_CHILD_MODIFIED
t, file:__wt0000.wt, session.checkpoint: aborting WiredTiger library