linux-hardening - Re: [PATCH 000/141] Fix fall-through warnings for Clang

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Message-ID: <CANiq72=n4rVvmKt0RCb5aOfQydA8bgDxfntRLDieV8Q2efP8Zg@mail.gmail.com>
Date:   Thu, 26 Nov 2020 18:05:45 +0100
From:   Miguel Ojeda <miguel.ojeda.sandonis@...il.com>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>
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Subject: Re: [PATCH 000/141] Fix fall-through warnings for Clang

On Thu, Nov 26, 2020 at 4:28 PM Geert Uytterhoeven <geert@...ux-m68k.org> wrote:
>
> The maintainer is not necessarily the owner/author of the code, and
> thus may not know the intent of the code.

Agreed, I was not blaming maintainers -- just trying to point out that
the problem is there :-)

In those cases, it is still very useful: we add the `fallthrough` and
a comment saying `FIXME: fallthrough intended? Figure this out...`.
Thus a previous unknown unknown is now a known unknown. And no new
unknown unknowns will be introduced since we enabled the warning
globally.

> BTW, you cannot mindlessly fix the latter, as you cannot know if
> "(a == b)" or "((a = b))" was intended, without understanding the code
> (and the (possibly unavailable) data sheet, and the hardware, ...).

That's right, I was referring to the cases where the compiler saves
someone time from a typo they just made.

Cheers,
Miguel