Re: [PATCH v4 0/3] mm, treewide: Rename kzfree() to kfree_sensitive()

Joe Perches
2020-06-16T19:02:51Z

On Mon, 2020-06-15 at 21:57 -0400, Waiman Long wrote:
> v4:
> - Break out the memzero_explicit() change as suggested by Dan Carpenter
> so that it can be backported to stable.
> - Drop the "crypto: Remove unnecessary memzero_explicit()" patch for
> now as there can be a bit more discussion on what is best. It will be
> introduced as a separate patch later on after this one is merged.

To this larger audience and last week without reply:
https://lore.kernel.org/lkml/573b3fbd5927c643920e1364230c296b23e7584d.camel@perches.com/

Are there _any_ fastpath uses of kfree or vfree?

Many patches have been posted recently to fix mispairings
of specific types of alloc and free functions.

To eliminate these mispairings at a runtime cost of four
comparisons, should the kfree/vfree/kvfree/kfree_const
functions be consolidated into a single kfree?

Something like the below:

void kfree(const void *addr)
{
if (is_kernel_rodata((unsigned long)addr))
return;

if (is_vmalloc_addr(addr))
_vfree(addr);
else
_kfree(addr);
}

#define kvfree kfree
#define vfree kfree
#define kfree_const kfree