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

Jo -l
2020-06-17T08:03:37Z

Bonjour,
Désolé, aucune traduction possible,
En français pour comprendre!
Merci
slts

> Le 17 06 2020 à 02:37, Matthew Wilcox <willy@infradead.org> a écrit :
>
> On Wed, Jun 17, 2020 at 01:01:30AM +0200, David Sterba wrote:
>> On Tue, Jun 16, 2020 at 11:53:50AM -0700, 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?
>>
>> I'd consider kfree performance critical for cases where it is called
>> under locks. If possible the kfree is moved outside of the critical
>> section, but we have rbtrees or lists that get deleted under locks and
>> restructuring the code to do eg. splice and free it outside of the lock
>> is not always possible.
>
> Not just performance critical, but correctness critical. Since kvfree()
> may allocate from the vmalloc allocator, I really think that kvfree()
> should assert that it's !in_atomic(). Otherwise we can get into trouble
> if we end up calling vfree() and have to take the mutex.

Jo-l
joel.voyer@gmail.com