Why is syscall auditing on with no rules?

[Andy Lutomirski]

On a stock Fedora installation:

$ sudo auditctl -l
No rules

Nonetheless TIF_SYSCALL_AUDIT is set and the __audit_syscall_entry and
__audit_syscall_exit account for >20% of syscall overhead according to
perf.

This sucks.  Unless I'm missing something, syscall auditing is *off*.

How hard would it be to arrange for TIF_SYSCALL_AUDIT to be cleared
when there are no syscall rules?

(This is extra bad in kernels before 3.13, where the clear call for
TIF_SYSCALL_AUDIT was completely missing.)

--Andy