On Mon, Mar 20, 2017 at 02:10:24PM +0000, David Laight wrote: > On x86 the cpu flags from the 'lock inc/dec' could be used to reasonably > cheaply detect errors - provided you actually generate a forwards branch. Note that currently there is no arch specific implementation. We could of course cure this. But note that the thing you propose; using the overflow flag, can only reasonably be done on PREEMPT=n kernels, otherwise we have an incredible number of contexts that can nest. Sure; getting all starts aligned to double overflow is incredibly rare, but I don't want to be the one to have to debug that.
