Summary:
With the code on main, `RunStressTest` increments the number of threads
one by one as the threads are created and started. This results in a
data race with `NonBatchedOpsStressTest::VerifyDb`, which reads this
value without synchronization, and is also not correct in the sense
that `VerifyDb` assumes that the number of threads already has its final
value set (e.g. it's checking whether the current thread is the last
one). The patch fixes this by setting the number of threads before
creating/starting any threads. This also eliminates the need for locking
the mutex during thread startup.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9466
Test Plan: Ran the blackbox crash test under TSAN for a while.
Reviewed By: ajkr
Differential Revision: D33858856
Pulled By: ltamasi
fbshipit-source-id: 8a6515a83fd1808b8b8dca61978777c4404f04cc
f07c56928f