I don't think this will work well. This can end up returning the same generated numbers to different threads, which we don't want.

Hmm in that case, should we change the algorithm(thread-safe one) or fine-grained locking for this use case?

I don't think there's a simple fix to the random module.

I commented on the issue. It'd be helpful to document the behavior and provide alternatives. For example, Java's java.util.Random includes the following comment:

Instances of java.util.Random are threadsafe. However, the concurrent use of the same java.util.Random instance across threads may encounter contention and consequent poor performance. Consider instead using ThreadLocalRandom in multithreaded designs.

I commented on the issue. It'd be helpful to document the behavior and provide alternatives. For example, Java's java.util.Random includes the following comment:

Okay sounds acceptable :)