linux-kernel - Re: [PATCH] w1: Use kfree_sensitive() instead of memset(0) and kfree()

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Message-Id: <581388A8-4FC3-4FC0-9D5B-9F13DCB90073@linux.dev>
Date: Mon, 30 Sep 2024 14:15:18 +0200
From: Thorsten Blum <thorsten.blum@...ux.dev>
To: Krzysztof Kozlowski <krzk@...nel.org>
Cc: linux-kernel@...r.kernel.org
Subject: Re: [PATCH] w1: Use kfree_sensitive() instead of memset(0) and
 kfree()

On 30. Sep 2024, at 13:50, Krzysztof Kozlowski <krzk@...nel.org> wrote:
> On 30/09/2024 13:44, Thorsten Blum wrote:
>> Use kfree_sensitive() to simplify w1_unref_slave() and remove the
>> following Coccinelle/coccicheck warning reported by
>> kfree_sensitive.cocci:
>> 
>> WARNING opportunity for kfree_sensitive/kvfree_sensitive
> 
> So are you fixing coccinelle just to hide the warning or actually fixing
> issue? Why this structure should be zeroed?

No issue, just a refactoring (+zeroing out) to silence the warning. The
structure probably doesn't need to be zeroed out, but why is it done
for DEBUG builds?

>> Signed-off-by: Thorsten Blum <thorsten.blum@...ux.dev>
>> ---
>> Please note: this change assumes that #ifdef DEBUG is no longer needed
>> and we should always zero out the memory.
> 
> But why are you assuming that? Your patch is not equivalent and I do not
> see any explanation in commit msg why is that.