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From:   SeongJae Park <sj@kernel.org>
To:     Rong Tao <rtoax@foxmail.com>
Cc:     sj@kernel.org, damon@lists.linux.dev, linux-kernel@vger.kernel.org,
        linux-kselftest@vger.kernel.org, linux-mm@kvack.org,
        rongtao@cestc.cn, shuah@kernel.org, yuanchu@google.com
Subject: Re: [PATCH] selftests/damon: Fix unnecessary compilation warnings
Date:   Fri, 11 Nov 2022 17:38:55 +0000
Message-Id: <20221111173855.108360-1-sj@kernel.org>
In-Reply-To: <tencent_32CBE47252C5F69571B40751DE6054082D05@qq.com>
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Hi Rong,


It would be better if you could notice the version of this patch using 'PATCH
v2' like subject prefix from next time.

On Fri, 11 Nov 2022 10:37:20 +0800 Rong Tao <rtoax@foxmail.com> wrote:

> From: Rong Tao <rongtao@cestc.cn>
> 
> When testing overflow and overread, there is no need to keep unnecessary
> compilation warnings, we should simply ignore them.
> 
> How to reproduce the problem:
> 
>     $ make -C tools/testing/selftests/
>     ...
>     warning: ‘write’ reading 4294967295 bytes from a region of size 1
>     [-Wstringop-overread]
>     warning: ‘read’ writing 4294967295 bytes into a region of size 25
>     overflows the destination [-Wstringop-overflow=]

Thank you for indenting as I suggested!  BTW, I'm ok to violate the line length
limit for quoting commands outputs.

> 
> Signed-off-by: Rong Tao <rongtao@cestc.cn>
> ---
>  tools/testing/selftests/damon/huge_count_read_write.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/tools/testing/selftests/damon/huge_count_read_write.c b/tools/testing/selftests/damon/huge_count_read_write.c
> index ad7a6b4cf338..8fbe276870e7 100644
> --- a/tools/testing/selftests/damon/huge_count_read_write.c
> +++ b/tools/testing/selftests/damon/huge_count_read_write.c
> @@ -8,6 +8,11 @@
>  #include <unistd.h>
>  #include <stdio.h>
>  
> +#pragma GCC diagnostic push
> +/* Ignore read(2) overflow and write(2) overread compile warnings */
> +#pragma GCC diagnostic ignored "-Wstringop-overread"

This still trigger below error on my old gcc.

    gcc -Wno-stringop-overread -Wno-stringop-overflow    huge_count_read_write.c  -o /home/sjpark/linux/tools/testing/selftests/damon/huge_count_read_write
    huge_count_read_write.c:13:32: warning: unknown option after ‘#pragma GCC diagnostic’ kind [-Wpragmas]
       13 | #pragma GCC diagnostic ignored "-Wstringop-overread"
          |                                ^~~~~~~~~~~~~~~~~~~~~
    cc1: warning: unrecognized command line option ‘-Wno-stringop-overread’

I don't think that's a blocker of this patch, but hope to hear your opinion.


Thanks,
SJ

> +#pragma GCC diagnostic ignored "-Wstringop-overflow"
> +
>  void write_read_with_huge_count(char *file)
>  {
>  	int filedesc = open(file, O_RDWR);
> @@ -27,6 +32,8 @@ void write_read_with_huge_count(char *file)
>  	close(filedesc);
>  }
>  
> +#pragma GCC diagnostic pop
> +
>  int main(int argc, char *argv[])
>  {
>  	if (argc != 2) {
> -- 
> 2.31.1
>