On Thu, Sep 05, 2019 at 07:28:01PM +0100, Al Viro wrote: > On Thu, Sep 05, 2019 at 08:23:03PM +0200, Christian Brauner wrote: > > > Because every caller of that function right now has that limit set > > anyway iirc. So we can either remove it from here and place it back for > > the individual callers or leave it in the helper. > > Also, I'm really asking, why not? Is it unreasonable to have an upper > > bound on the size (for a long time probably) or are you disagreeing with > > PAGE_SIZE being used? PAGE_SIZE limit is currently used by sched, perf, > > bpf, and clone3 and in a few other places. > > For a primitive that can be safely used with any size (OK, any within > the usual 2Gb limit)? Why push the random policy into the place where > it doesn't belong? Ah, the "not in the helper part" makes sense. As long as leave the check for the callers themselves. > > Seriously, what's the point? If they want to have a large chunk of > userland memory zeroed or checked for non-zeroes - why would that > be a problem?