gettimeofday((void *)-1, NULL) implicates core dump on recent FreeBSD 11-CURRENT

[Konstantin Belousov]

On Thu, Jul 09, 2015 at 08:27:17AM +1000, Peter Jeremy wrote:
> I'm not sure if we want to explicitly document the conditions under which
> gettimeofday() (or clock_gettime()) are implemented in userland vs syscalls
> because that is guaranteed to get stale over time.  How about stating that
Of course, we don't.  There is no guarantee that the set of conditions
is stable even on the stable branch.

> these functions are implemented as syscalls only if the AT_TIMEKEEP value
> reported by "procstat -x" is NULL.
Mere presence of AT_TIMEKEEP does not imply the use of the fast path.
E.g. the fast path can be disabled dynamically, or timecounter could be
changed, or libc might be of the wrong version.  My imagination stops
there.

IMO the point of this discussion is to note that test suite tests useless
things.  If somebody run the test suite for libc, she would immediately note
another failing test for the stack protector, which is similar to the
gettimeofday nonsense.