Re: [PATCH xfsprogs-5.14.2 URGENT] libxfs: hide the drainbamaged fallthrough macro from xfslibs

Kees Cook
2021-12-06T20:15:06Z

On Sun, Dec 05, 2021 at 09:49:51AM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
>
> Back in mid-2021, Kees and Gustavo rammed into the kernel a bunch of
> static checker "improvements" that redefined '/* fallthrough */'
> comments for switch statements as a macro that virtualizes either that
> same comment, a do-while loop, or a compiler __attribute__. This was
> necessary to work around the poor decision-making of the clang, gcc, and
> C language standard authors, who collectively came up with four mutually
> incompatible ways to document a lack of branching in a code flow.
>
> Having received ZERO HELP porting this to userspace, Eric and I

Look, I know you don't like this feature, but claiming that you received
no help with it is just false. I explicitly offered to help with xfsprogs,
and even sent a first-attempt at a patch to do so[1], which looks very
similar to what you've got here, almost 6 months later. I even went
through and changed all the comments to an explicitly XFS-specific
macro when you made it clear you hated the statement-like "fallthrough"
macro name.

I continue to be baffled about this whole saga. We're all trying to help
make Linux better, and I went out of my way to help with xfsprogs too to
minimize the impact on you (since you said you wanted to have nothing to
do with it), yet Gustavo and I got continually flamed by yourself and
Dave, including even now in this very misleading commit log.

What is going on here?

-Kees

[1] https://lore.kernel.org/lkml/202105280915.9117D7C@keescook/

--
Kees Cook