[quotemstr]

32 bits is still too small. I wouldn't be comfortable relying on the size of the PID space to avoid collisions until we made it 128 bits or so. I think you're still seriously overestimating the danger of a DoS here: whatever limits apply to forked processes can apply to process handles. Whatever mitigates fork bombs will also mitigate handle-based attacks.

The advantages of process handles outweigh this small risk.

[Dylan16807]

In what scenario would you run out of 64 bit PIDs? How many per second for how many centuries?

[quotemstr]

It's not a matter of running out of PIDs: it's about the probability of accidental collision.