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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Tue, 23 Aug 2022 16:57:00 -0700
Message-ID: <CAHk-=wiwr2Ff_1SKzRkjSbNLFYfk4KurvZhLuwVuTT-m9w5_6A@mail.gmail.com>
Subject: Re: [for-linus][PATCH 01/10] tracing: Suppress sparse warnings
 triggered by is_signed_type()
To:     Bart Van Assche <bvanassche@acm.org>,
        Al Viro <viro@zeniv.linux.org.uk>
Cc:     Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Steven Rostedt <rostedt@goodmis.org>,
        linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Christoph Hellwig <hch@lst.de>,
        Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
        Jens Axboe <axboe@kernel.dk>
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On Tue, Aug 23, 2022 at 4:18 PM Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> Can you try the sparse version at
>
>    git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/sparse.git
>
> which I just set up temporarily with some patches of mine.

Ugh, and while testing this with sparse, I noticed that sparse itself
got that whole 'is_signed_type()' check wrong.

The sparse fix was to remove one line of code, but that one worries
me, because that one line was clearly very intentional:

   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/sparse.git/commit/?id=7e5f1c2eba1426e414698071dd0de7d039eb385d

Adding Al, since he's actually the original source of that bitwise
code (and did a lot of other sparse code on the type handling and
preprocessor side in particular).

             Linus