$ vmstat -m | grep -i accf
               accf     118   2.79K       0    390M    3.04K
$ cd /tmp/poc && time ./race_attach 5000 8
iterations=5000 threads=8
iterations with >=2 attach successes (leaked so_accf+str): 178
iterations with exactly 1 success: 4822
iterations with 0 successes: 0
        7.71 real         0.18 user         0.72 sys
$ vmstat -m | grep -i accf
               accf     299   7.03K       0    390M    8.10K
# +181 chunks (>=178 wins; iterations where 3+ threads won leak 2+, hence the
# small delta between the counter and the chunk count). Leak is repeatable.