linux-kernel - Re: [PATCH 06/12] selftests/nolibc: avoid passing NULL to printf("%s")

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Message-ID: <20240803093355.GC29127@1wt.eu>
Date: Sat, 3 Aug 2024 11:33:55 +0200
From: Willy Tarreau <w@....eu>
To: Thomas Weißschuh <linux@...ssschuh.net>
Cc: Shuah Khan <shuah@...nel.org>, linux-kernel@...r.kernel.org,
        linux-kselftest@...r.kernel.org
Subject: Re: [PATCH 06/12] selftests/nolibc: avoid passing NULL to
 printf("%s")

On Sun, Jul 28, 2024 at 12:10:00PM +0200, Thomas Weißschuh wrote:
> Clang on higher optimization levels detects that NULL is passed to
> printf("%s") and warns about it.
> Avoid the warning.

I don't see why this would be a problem, we do explicitly check for
NULL in our printf implementation and print "(null)". Or maybe it is
upset due to the attribute(printf) ? I don't know what the standard
says regarding %s and NULL, though. If it says that NULL is forbidden
then I can understand the warning and your fix is indeed correct. In
any case it's not worth fighting with a compiler for nolibc-test, but
it's probably worth mentioning in the commit message that it warns
despite the check being already done.

Willy