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Date:   Thu, 13 May 2021 13:03:50 -0700
Message-Id: <20210513200350.854429-1-davidgow@google.com>
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Subject: [PATCH] kunit: Add gnu_printf specifiers
From:   David Gow <davidgow@google.com>
To:     Brendan Higgins <brendanhiggins@google.com>,
        Shuah Khan <skhan@linuxfoundation.org>
Cc:     linux-kselftest@vger.kernel.org, kunit-dev@googlegroups.com,
        linux-kernel@vger.kernel.org, David Gow <davidgow@google.com>
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Some KUnit functions use variable arguments to implement a printf-like
format string. Use the __printf() attribute to let the compiler warn if
invalid format strings are passed in.

If the kernel is build with W=3D1, it complained about the lack of these
specifiers, e.g.:
../lib/kunit/test.c:72:2: warning: function =E2=80=98kunit_log_append=E2=80=
=99 might be a candidate for =E2=80=98gnu_printf=E2=80=99 format attribute =
[-Wsuggest-attribute=3Dformat]

Signed-off-by: David Gow <davidgow@google.com>
---
 include/kunit/test.h      | 2 +-
 lib/kunit/string-stream.h | 6 +++---
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/kunit/test.h b/include/kunit/test.h
index 49601c4b98b8..af2e386b867c 100644
--- a/include/kunit/test.h
+++ b/include/kunit/test.h
@@ -610,7 +610,7 @@ static inline void *kunit_kzalloc(struct kunit *test, s=
ize_t size, gfp_t gfp)
=20
 void kunit_cleanup(struct kunit *test);
=20
-void kunit_log_append(char *log, const char *fmt, ...);
+void __printf(2, 3) kunit_log_append(char *log, const char *fmt, ...);
=20
 /*
  * printk and log to per-test or per-suite log buffer.  Logging only done
diff --git a/lib/kunit/string-stream.h b/lib/kunit/string-stream.h
index fe98a00b75a9..5e94b623454f 100644
--- a/lib/kunit/string-stream.h
+++ b/lib/kunit/string-stream.h
@@ -35,9 +35,9 @@ struct string_stream *alloc_string_stream(struct kunit *t=
est, gfp_t gfp);
 int __printf(2, 3) string_stream_add(struct string_stream *stream,
 				     const char *fmt, ...);
=20
-int string_stream_vadd(struct string_stream *stream,
-		       const char *fmt,
-		       va_list args);
+int __printf(2, 0) string_stream_vadd(struct string_stream *stream,
+				      const char *fmt,
+				      va_list args);
=20
 char *string_stream_get_string(struct string_stream *stream);
=20
--=20
2.31.1.751.gd2f1c929bd-goog