On Mon, Apr 13, 2020 at 05:15:49PM -0400, Waiman Long wrote: > As said by Linus: > > A symmetric naming is only helpful if it implies symmetries in use. > Otherwise it's actively misleading. As the btrfs example proves - people can be tempted by this false symmetry to pair kzalloc with kzfree, which isn't what we wanted. > In "kzalloc()", the z is meaningful and an important part of what the > caller wants. > > In "kzfree()", the z is actively detrimental, because maybe in the > future we really _might_ want to use that "memfill(0xdeadbeef)" or > something. The "zero" part of the interface isn't even _relevant_. > > The main reason that kzfree() exists is to clear sensitive information > that should not be leaked to other future users of the same memory > objects. > > Rename kzfree() to kfree_sensitive() to follow the example of the > recently added kvfree_sensitive() and make the intention of the API > more explicit. In addition, memzero_explicit() is used to clear the > memory to make sure that it won't get optimized away by the compiler. > > The renaming is done by using the command sequence: > > git grep -w --name-only kzfree |\ > xargs sed -i 's/\bkzfree\b/kfree_sensitive/' > > followed by some editing of the kfree_sensitive() kerneldoc and the > use of memzero_explicit() instead of memset(). > > Suggested-by: Joe Perches <joe@xxxxxxxxxxx> > Signed-off-by: Waiman Long <longman@xxxxxxxxxx> Looks good to me. Thanks for fixing this very old mistake. Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
