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Date:   Tue, 14 Apr 2020 11:01:29 +0200
From:   Michal Hocko <mhocko@kernel.org>
To:     Waiman Long <longman@redhat.com>
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Subject: Re: [PATCH 1/2] mm, treewide: Rename kzfree() to kfree_sensitive()
Message-ID: <20200414090129.GE4629@dhcp22.suse.cz>
References: <20200413211550.8307-1-longman@redhat.com>
 <20200413211550.8307-2-longman@redhat.com>
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On Mon 13-04-20 17:15:49, Waiman Long wrote:
> As said by Linus:
> 
>   A symmetric naming is only helpful if it implies symmetries in use.
>   Otherwise it's actively misleading.
> 
>   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@perches.com>
> Signed-off-by: Waiman Long <longman@redhat.com>

Makes sense. I haven't checked all the conversions and will rely on the
script doing the right thing. The core MM part is correct.

Acked-by: Michal Hocko <mhocko@suse.com>
-- 
Michal Hocko
SUSE Labs