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Subject: Re: [PATCH] selftests/exec: Avoid future NULL argv execve warning
To:     Alexey Dobriyan <adobriyan@gmail.com>
Cc:     Kees Cook <keescook@chromium.org>,
        Eric Biederman <ebiederm@xmission.com>,
        Shuah Khan <shuah@kernel.org>, linux-kselftest@vger.kernel.org,
        Ariadne Conill <ariadne@dereferenced.org>,
        Michael Kerrisk <mtk.manpages@gmail.com>,
        Matthew Wilcox <willy@infradead.org>,
        Christian Brauner <brauner@kernel.org>,
        Rich Felker <dalias@libc.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-hardening@vger.kernel.org,
        Shuah Khan <skhan@linuxfoundation.org>
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From:   Shuah Khan <skhan@linuxfoundation.org>
Message-ID: <942a078a-2b27-d028-0617-714b6f597942@linuxfoundation.org>
Date:   Fri, 4 Feb 2022 09:11:53 -0700
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On 2/2/22 2:00 PM, Alexey Dobriyan wrote:
> On Wed, Feb 02, 2022 at 10:38:57AM -0700, Shuah Khan wrote:
>> On 2/2/22 8:13 AM, Alexey Dobriyan wrote:
>>> On Mon, Jan 31, 2022 at 04:08:07PM -0800, Kees Cook wrote:
>>>> Build actual argv for launching recursion test to avoid future warning
>>>> about using an empty argv in execve().
>>>
>>>> --- a/tools/testing/selftests/exec/recursion-depth.c
>>>> +++ b/tools/testing/selftests/exec/recursion-depth.c
>>>> @@ -24,8 +24,14 @@
>>>>    #include <sys/mount.h>
>>>>    #include <unistd.h>
>>>> +#define FILENAME "/tmp/1"
>>>> +#define HASHBANG "#!" FILENAME "\n"
>>>> +
>>>>    int main(void)
>>>>    {
>>>> +	char * const argv[] = { FILENAME, NULL };
>>>> +	int rv;
>>>
>>> Can we move out of -Wdeclaration-after-statement mentality in tests at least?
>>
>> selftest like the rest of the kernel follows the same coding guidelines.
>> It will follow the moving "-Wdeclaration-after-statement mentality" when
>> the rest of the kernel does.
>>
>> Looks like this topic was discussed in the following:
>> https://patchwork.kernel.org/project/linux-kbuild/patch/c6fda26e8d134264b04fadc3386d6c32@gmail.com/
> 
> The only real argument is "gcc miscompiles /proc" to which adding -Wdeclaration-after-statement
> looks like a too big hammer.
> 

Either way - selftest will stay in sync with the kernel coding standards
for good reasons. Doing its own thing confuses developers and makes it
hard for maintainers.

thanks,
-- Shuah