[gowld]

Allowing any process to arbitrarily modify the state of another process would be a disaster for stability and security.

[colejohnson66]

Isn’t that what a debugger does?

[Someone]

Yes, and it is a disaster for stability and security. The designers of dtrace worked hard on the stability part. See, for example, the section on DIF safety in https://www.cs.princeton.edu/courses/archive/fall04/cos518/p....