Redis When unit tests (UTs) are executed concurrently in a multi - threaded environment without locks, it can lead to port duplication, which in turn causes the UTs to fail.

https://github.com/redis/redis/blob/695126cccef67ddf4591da970b62b1efe175ac7c/tests/support/util.tcl#L494

Comment From: ShooterIT

don't completely follow you, could you show steps to reproduction?