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

Denis Efremov
2020-06-17T21:37:10Z

On 6/16/20 9:53 PM, Joe Perches wrote:
> 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.

I've prepared a coccinelle script to highlight these mispairings in a function
a couple of days ago: https://lkml.org/lkml/2020/6/5/953
I've listed all the fixes in the commit message.

Not so many mispairings actually, and most of them are harmless like:
kmalloc(E) -> kvfree(E)

However, coccinelle script can't detect cross-functions mispairings, i.e.
allocation in one function, free in another funtion.

Thanks,
Denis