Re: [RFC]: mm,power: introduce MADV_WIPEONSUSPEND

On Mon, Jul 6, 2020 at 2:27 PM Alexander Graf [off-list ref] wrote:

Unless we create a vsyscall that returns both the PID as well as the
epoch and thus handles fork *and* suspend. I need to think about this a
bit more :).

You can't reliably detect forking by checking the PID if it is
possible for multiple forks to be chained before the reuse check runs:

 - pid 1000 remembers its PID
 - pid 1000 forks, creating child pid 1001
 - pid 1000 exits and is waited on by init
 - the pid allocator wraps around
 - pid 1001 forks, creating child pid 1000
 - child with pid 1000 tries to check for forking, determines that its
PID is 1000, and concludes that it is still the original process