On Tue, Apr 07, 2020 at 04:45:45PM -0400, Waiman Long wrote: > On 4/7/20 4:31 PM, Joe Perches wrote: > > On Tue, 2020-04-07 at 16:03 -0400, Waiman Long wrote: > >> +extern void kvfree_sensitive(const void *addr, size_t len); > > Why should size_t len be required? > > > > Why not do what kzfree does and memset > > the entire allocation? (area->size) > > If the memory is really virtually mapped, the only way to find out the > size of the object is to use find_vm_area() which can be relatively high > cost and no simple helper function is available. On the other hand, the > length is readily available in the callers. So passing the length > directly to the kvfree_sensitive is simpler. Also it lets us zero only the first N bytes of the allocation. That might be good for performance, if only the first N bytes of an M byte allocation are actually sensitive. I don't know if we have any such cases, but they could exist.
