Leap seconds can make time go both ways, but adding them makes time stop/go back because 24:00:00 cannot be represented as 1/86400 part of day N instead of day N+1 on major OSes. And they were only added so far.
It doesn’t work like that. UTC goes forward always. Leap seconds are scheduled and known in advance. NTP time services will just smear time advancement a little to account for an additional second. Time never has to go backwards. This is how Google does it.
Leap seconds can make time go both ways, but adding them makes time stop/go back because 24:00:00 cannot be represented as 1/86400 part of day N instead of day N+1 on major OSes. And they were only added so far.
It doesn’t work like that. UTC goes forward always. Leap seconds are scheduled and known in advance. NTP time services will just smear time advancement a little to account for an additional second. Time never has to go backwards. This is how Google does it.
This is how Google does it in their datacenters, but not major OSes by default