MIME-Version: 1.0
From:   Alexander Potapenko <glider@google.com>
Date:   Fri, 3 Mar 2023 15:28:12 +0100
Message-ID: <CAG_fn=WZnBtRujLyhouz1AmerSKB71oPej442JDOw2OaORbWQg@mail.gmail.com>
Subject: Infinite loop in checkpatch.pl
To:     apw@canonical.com, Joe Perches <joe@perches.com>,
        dwaipayanray1@gmail.com, Lukas Bulwahn <lukas.bulwahn@gmail.com>
Cc:     LKML <linux-kernel@vger.kernel.org>
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Hi folks,

I've noticed that checkpatch.pl chokes on the following file (also attached=
):

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D
$ cat test-checkpatch.txt
diff --git a/mm/kmsan/kmsan_test.c b/mm/kmsan/kmsan_test.c
@@ -504,6 +504,25 @@ static void
test_memcpy_aligned_to_unaligned2(struct kunit *test)
+ EXPECTATION_NO_REPORT(expect);                              \
+ volatile uint##size##_t uninit;                             \
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D


, getting into an infinite loop in annotate_values().
The following patch helps it to proceed:

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 78cc595b98ce1..01d998b416a51 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2240,8 +2240,13 @@ sub annotate_values {
                        print "C($1)\n" if ($dbg_values > 1);
                }
                if (defined $1) {
-                       $cur =3D substr($cur, length($1));
-                       $res .=3D $type x length($1);
+                       if (length($1)) {
+                               $cur =3D substr($cur, length($1));
+                               $res .=3D $type x length($1);
+                       } else {
+                               $res .=3D $cur;
+                               $cur =3D "";
+                       }
                }
        }

, but I have no idea how to test it properly.

Could you please take a look?


Thanks,
Alex

--=20
Alexander Potapenko
Software Engineer

Google Germany GmbH
Erika-Mann-Stra=C3=9Fe, 33
80636 M=C3=BCnchen

Gesch=C3=A4ftsf=C3=BChrer: Paul Manicle, Liana Sebastian
Registergericht und -nummer: Hamburg, HRB 86891
Sitz der Gesellschaft: Hamburg

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