search for: test_known_hosts

...on succeeds, but it fails to delete the temporary file on exit, OR 2. It fails to link "known_hosts.old" and the operation fails. I've attached a Python (3) program that reliably reproduces the issue on all of the above versions and OSes. The program generates a test file named "test_known_hosts" containing 100 hosts, then attempts to use `ssh-keygen -R` to remove all of those hosts on 100 separate threads concurrently. Running the Python program will, more often than not, leave a collection of temp files remaining as well as log a few "known_hosts.old"-based failures, in w...