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From:   Andrey Konovalov <andreyknvl@gmail.com>
Date:   Thu, 9 Feb 2023 23:21:08 +0100
Message-ID: <CA+fCnZfKAF3AF+m0_Jpv8Di3G7ZOLe5-TBXuLiASCC7y1Onjsg@mail.gmail.com>
Subject: Re: [PATCH] kasan: use %zd format for printing size_t
To:     Arnd Bergmann <arnd@kernel.org>
Cc:     Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Marco Elver <elver@google.com>, kasan-dev@googlegroups.com,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
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On Wed, Feb 1, 2023 at 8:13 AM Arnd Bergmann <arnd@kernel.org> wrote:
>
> From: Arnd Bergmann <arnd@arndb.de>
>
> The size_t type depends on the architecture, so %lu does not work
> on most 32-bit ones:
>
> In file included from include/kunit/assert.h:13,
>                  from include/kunit/test.h:12,
>                  from mm/kasan/report.c:12:
> mm/kasan/report.c: In function 'describe_object_addr':
> include/linux/kern_levels.h:5:25: error: format '%lu' expects argument of type 'long unsigned int', but argument 5 has type 'size_t' {aka 'unsigned int'} [-Werror=format=]
> mm/kasan/report.c:270:9: note: in expansion of macro 'pr_err'
>   270 |         pr_err("The buggy address is located %d bytes %s of\n"
>       |         ^~~~~~
>
> Fixes: 0e301731f558 ("kasan: infer allocation size by scanning metadata")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  mm/kasan/report.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/kasan/report.c b/mm/kasan/report.c
> index e0492124e90a..89078f912827 100644
> --- a/mm/kasan/report.c
> +++ b/mm/kasan/report.c
> @@ -268,7 +268,7 @@ static void describe_object_addr(const void *addr, struct kasan_report_info *inf
>         }
>
>         pr_err("The buggy address is located %d bytes %s of\n"
> -              " %s%lu-byte region [%px, %px)\n",
> +              " %s%zu-byte region [%px, %px)\n",
>                rel_bytes, rel_type, region_state, info->alloc_size,
>                (void *)object_addr, (void *)(object_addr + info->alloc_size));
>  }
> --
> 2.39.0
>

Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>

Thanks!