DAVEM TPF Grant#3 April 2026 report

Last month I continued looking into race conditions in threads and
threads::shared. I have now reached the point where the threads-related
test suite can run cleanly under 'valgrind --tool=helgrind'. But there
is still an occasional crash in blocks.t  when run repeatedly for many
hours in parallel on 20 terminals, which I am currently working on. I'm
hopeful that once that is fixed, the branch will be ready to push.

SUMMARY:
     33:35 GH #24258 dist/threads/t/free.t: Rare test failure in debugging build on FreeBSD