linux-kernel - Re: [PATCH v4] lib/test_printf.c: fix clang -Wformat warnings

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Message-ID: <Ytag6youpnmli3E1@alley>
Date:   Tue, 19 Jul 2022 14:17:47 +0200
From:   Petr Mladek <pmladek@...e.com>
To:     Justin Stitt <justinstitt@...gle.com>
Cc:     ndesaulniers@...gle.com, andriy.shevchenko@...ux.intel.com,
        linux-kernel@...r.kernel.org, llvm@...ts.linux.dev,
        nathan@...nel.org, rostedt@...dmis.org, senozhatsky@...omium.org,
        trix@...hat.com
Subject: Re: [PATCH v4] lib/test_printf.c: fix clang -Wformat warnings

On Mon 2022-07-18 16:06:26, Justin Stitt wrote:
> see warnings:
> | lib/test_printf.c:157:52: error: format specifies type 'unsigned char'
> | but the argument has type 'int' [-Werror,-Wformat]
> test("0|1|1|128|255",
> | "%hhu|%hhu|%hhu|%hhu|%hhu", 0, 1, 257, 128, -1);
> -
> | lib/test_printf.c:158:55: error: format specifies type 'char' but the
> | argument has type 'int' [-Werror,-Wformat] test("0|1|1|-128|-1",
> | "%hhd|%hhd|%hhd|%hhd|%hhd", 0, 1, 257, 128, -1);
> -
> | lib/test_printf.c:159:41: error: format specifies type 'unsigned
> short'
> | but the argument has type 'int' [-Werror,-Wformat]
> | test("2015122420151225", "%ho%ho%#ho", 1037, 5282, -11627);
> 
> There's an ongoing movement to eventually enable the -Wformat flag for
> clang. Previous patches have targeted incorrect usage of
> format specifiers. In this case, however, the "incorrect" format
> specifiers are intrinsically part of the test cases. Hence, fixing them
> would be misaligned with their intended purpose. My proposed fix is to
> simply disable the warnings so that one day a clean build of the kernel
> with clang (and -Wformat enabled) would be possible. It would also keep
> us in the green for alot of the CI bots.
> 
> Link: https://github.com/ClangBuiltLinux/linux/issues/378
> Suggested-by: Nathan Chancellor <nathan@...nel.org>
> Suggested-by: Nick Desaulniers <ndesaulniers@...gle.com>
> Signed-off-by: Justin Stitt <justinstitt@...gle.com>

Looks good to me:

Reviewed-by: Petr Mladek <pmladek@...e.com>

Best Regards,
Petr