Re: [PATCH] wireless: ath: work around false-positive stringop-overread warning

From: "Arnd Bergmann" <arnd@arndb.de>
To: "Kalle Valo" <kvalo@kernel.org>
Cc: "Arnd Bergmann" <arnd@kernel.org>,
	Netdev <netdev@vger.kernel.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] wireless: ath: work around false-positive stringop-overread warning
Date: Mon, 08 May 2023 17:07:49 +0200	[thread overview]
Message-ID: <c7f88295-2e22-4100-b9c8-feb380b64359@app.fastmail.com> (raw)
In-Reply-To: <87mt2eoopo.fsf@kernel.org>

On Mon, May 8, 2023, at 16:57, Kalle Valo wrote:
> "Arnd Bergmann" <arnd@arndb.de> writes:
>>
>> I uploaded gcc-13.1.0 binaries last week, but still need to
>> update the html page, so it's not yet linked. You can navigate
>> the directories from the gcc-12 builds.
>
> Thanks! I was able to find the build[1] but having an issue:
>
> $ ./x86_64-linux-gcc -v
> ./x86_64-linux-gcc: /lib/x86_64-linux-gnu/libc.so.6: version 
> `GLIBC_2.35' not found (required by ./x86_64-linux-gcc)
> ./x86_64-linux-gcc: /lib/x86_64-linux-gnu/libc.so.6: version 
> `GLIBC_2.32' not found (required by ./x86_64-linux-gcc)
> ./x86_64-linux-gcc: /lib/x86_64-linux-gnu/libc.so.6: version 
> `GLIBC_2.33' not found (required by ./x86_64-linux-gcc)
> ./x86_64-linux-gcc: /lib/x86_64-linux-gnu/libc.so.6: version 
> `GLIBC_2.36' not found (required by ./x86_64-linux-gcc)
> ./x86_64-linux-gcc: /lib/x86_64-linux-gnu/libc.so.6: version 
> `GLIBC_2.34' not found (required by ./x86_64-linux-gcc)
>
> With older GCC versions from your page I don't have this problem. I'm
> using Debian 10 still so so is my libc too old?

(dropping most Cc)

Indeed, thanks for the report, I forgot about that issue. I used
to build the cross toolchains in an old Ubuntu 16.04 chroot to avoid
that issue, and I linked all other dependencies statically.

The gcc-13.1.0 builds are the first ones I did on an arm64 machine,
so I had to create a new build environment and started out with
just my normal Debian testing rootfs, which caused me enough issues
to figure out first.

I had previously experimented with linking statically against
musl to avoid all other dependencies, but that ended up with
slower binaries because the default memory allocator in musl
doesn't work that well for gcc, and I never quite figured out
how to pick a different memory allocator, or which one to use.

I should probably just pick an older Debian release that is new
enough to contain cross compilers for arm64 and x86 and then
set up the same kind of chroot I had in before.

      Arnd