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Date:   Wed, 6 Dec 2023 10:55:51 +0100
From:   Petr Mladek <pmladek@suse.com>
To:     Joel Granados <j.granados@samsung.com>
Cc:     Luis Chamberlain <mcgrof@kernel.org>, willy@infradead.org,
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Subject: Re: [PATCH 07/10] printk: Remove the now superfluous sentinel
 elements from ctl_table array
Message-ID: <ZXBFJ3G9ERfI55Sc@alley>
References: <20231107-jag-sysctl_remove_empty_elem_kernel-v1-0-e4ce1388dfa0@samsung.com>
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On Mon 2023-12-04 09:56:28, Joel Granados wrote:
> Hey Petr
> 
> I missed this message somehow....
> 
> On Tue, Nov 28, 2023 at 03:07:43PM +0100, Petr Mladek wrote:
> > On Tue 2023-11-07 14:45:07, Joel Granados via B4 Relay wrote:
> > > From: Joel Granados <j.granados@samsung.com>
> > > 
> > > This commit comes at the tail end of a greater effort to remove the
> > > empty elements at the end of the ctl_table arrays (sentinels) which
> > > will reduce the overall build time size of the kernel and run time
> > > memory bloat by ~64 bytes per sentinel (further information Link :
> > > https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)
> > > 
> > > rm sentinel element from printk_sysctls
> > > 
> > > Signed-off-by: Joel Granados <j.granados@samsung.com>
> > 
> > I am a bit sceptical if the size and time reduction is worth the
> > effort. I feel that this change makes the access a bit less secure.
> In what way "less secure"? Can you expand on that?
> 
> Notice that if you pass a pointer to the register functions, you will
> get a warning/error on compilation.

I have vague memories that some arrays were not static or the length
has been somehow manipulated. But I might be wrong.

You are right that it should be safe with the static arrays.
And the NULL sentinel might be more error-prone after all.

Let's forget my mumbles.

Best Regards,
Petr