Re: [PATCH v7 15/25] scripts: checkpatch: diagnose uses of `%pA` in the C side

From: Joe Perches <joe@perches.com>
To: Miguel Ojeda <ojeda@kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org,
	Jarkko Sakkinen <jarkko@kernel.org>,
	Kees Cook <keescook@chromium.org>,
	Alex Gaynor <alex.gaynor@gmail.com>,
	Wedson Almeida Filho <wedsonaf@google.com>,
	Andy Whitcroft <apw@canonical.com>,
	Dwaipayan Ray <dwaipayanray1@gmail.com>,
	Lukas Bulwahn <lukas.bulwahn@gmail.com>
Subject: Re: [PATCH v7 15/25] scripts: checkpatch: diagnose uses of `%pA` in the C side
Date: Sun, 22 May 2022 19:17:29 -0700	[thread overview]
Message-ID: <9ff72e47bf89977efe00df6db6ebbdd7b22a9972.camel@perches.com> (raw)
In-Reply-To: <20220523020209.11810-16-ojeda@kernel.org>

On Mon, 2022-05-23 at 04:01 +0200, Miguel Ojeda wrote:
> The `%pA` format specifier is only intended to be used from Rust.
> 
> `checkpatch.pl` already gives a warning for invalid specificers:
> 
>     WARNING: Invalid vsprintf pointer extension '%pA'
> 
> With this change, we introduce an error message with further
> explanation:
> 
>     ERROR: '%pA' is only intended to be used from Rust code
> 
> Suggested-by: Kees Cook <keescook@chromium.org>
> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

How many developers are required for a trivial patch?

> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
> @@ -6784,6 +6784,10 @@ sub process {
>  					my $stat_real = get_stat_real($linenr, $lc);
>  					my $ext_type = "Invalid";
>  					my $use = "";
> +					if ($bad_specifier =~ /pA/) {
> +						ERROR("VSPRINTF_RUST",
> +							"'\%pA' is only intended to be used from Rust code\n" . "$here\n$stat_real\n");
> +					}
>  					if ($bad_specifier =~ /p[Ff]/) {

and this should now use elsif

>  						$use = " - use %pS instead";
>  						$use =~ s/pS/ps/ if ($bad_specifier =~ /pf/);