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From:   Miguel Ojeda <ojeda@kernel.org>
To:     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>,
        Miguel Ojeda <ojeda@kernel.org>,
        Kees Cook <keescook@chromium.org>,
        Alex Gaynor <alex.gaynor@gmail.com>,
        Wedson Almeida Filho <wedsonaf@google.com>,
        Andy Whitcroft <apw@canonical.com>,
        Joe Perches <joe@perches.com>,
        Dwaipayan Ray <dwaipayanray1@gmail.com>,
        Lukas Bulwahn <lukas.bulwahn@gmail.com>
Subject: [PATCH v7 15/25] scripts: checkpatch: diagnose uses of `%pA` in the C side
Date:   Mon, 23 May 2022 04:01:28 +0200
Message-Id: <20220523020209.11810-16-ojeda@kernel.org>
In-Reply-To: <20220523020209.11810-1-ojeda@kernel.org>
References: <20220523020209.11810-1-ojeda@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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>
---
 scripts/checkpatch.pl | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 577e02998701..457d544b0b9d 100755
--- 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]/) {
 						$use = " - use %pS instead";
 						$use =~ s/pS/ps/ if ($bad_specifier =~ /pf/);
-- 
2.36.1