I'm not too familiar with Fuchsia, but other syscalls return ZX_ERR_INVALID_ARGS so I suspect the idea was to keep this particular, security-critical call as si

I'm not too familiar with Fuchsia, but other syscalls return ZX_ERR_INVALID_ARGS so I suspect the idea was to keep this particular, security-critical call as simple as possible. This behavior shouldn't break any code that wasn't already broken.