Date:   Mon, 15 Nov 2021 16:31:09 -0800
From:   Kees Cook <keescook@chromium.org>
To:     Marco Elver <elver@google.com>
Cc:     Geert Uytterhoeven <geert@linux-m68k.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Nick Terrell <terrelln@fb.com>,
        Rob Clark <robdclark@gmail.com>,
        "James E.J. Bottomley" <James.Bottomley@hansenpartnership.com>,
        Helge Deller <deller@gmx.de>,
        Anton Altaparmakov <anton@tuxera.com>,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        Sergio Paracuellos <sergio.paracuellos@gmail.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Joey Gouly <joey.gouly@arm.com>,
        Stan Skowronek <stan@corellium.com>,
        Hector Martin <marcan@marcan.st>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        =?iso-8859-1?Q?Andr=E9?= Almeida <andrealmeid@collabora.com>,
        Peter Zijlstra <peterz@infradead.org>,
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        kasan-dev <kasan-dev@googlegroups.com>
Subject: Re: Build regressions/improvements in v5.16-rc1
Message-ID: <202111151624.91EDCFF7@keescook>
References: <20211115155105.3797527-1-geert@linux-m68k.org>
 <CAMuHMdUCsyUxaEf1Lz7+jMnur4ECwK+JoXQqmOCkRKqXdb1hTQ@mail.gmail.com>
 <YZKOce4XhAU49+Yn@elver.google.com>
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On Mon, Nov 15, 2021 at 05:44:33PM +0100, Marco Elver wrote:
> On Mon, Nov 15, 2021 at 05:12PM +0100, Geert Uytterhoeven wrote:
> [...]
> > >   + /kisskb/src/include/linux/fortify-string.h: error: call to '__read_overflow' declared with attribute error: detected read beyond size of object (1st parameter):  => 263:25, 277:17
> > 
> >     in lib/test_kasan.c
> > 
> > s390-all{mod,yes}config
> > arm64-allmodconfig (gcc11)
> 
> Kees, wasn't that what [1] was meant to fix?
> [1] https://lkml.kernel.org/r/20211006181544.1670992-1-keescook@chromium.org

[1] fixed the ones I found when scanning for __write_overflow(). [2]
fixed some others, so it's possible there are yet more to fix?

Taking a look at Linus's tree, though, the "263" and "277" lines don't
line up correctly. I'll go see if I can reproduce this. Is this with
W=1?

-Kees

[2] https://www.ozlabs.org/~akpm/mmotm/broken-out/kasan-test-consolidate-workarounds-for-unwanted-__alloc_size-protection.patch


-- 
Kees Cook