From: Nathan Chancellor <nathan@kernel.org>
To: Justin Stitt <justinstitt@google.com>
Cc: ndesaulniers@google.com, arnd@arndb.de,
gregkh@linuxfoundation.org, keescook@chromium.org,
linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
trix@redhat.com
Subject: Re: [PATCH v2] drivers: lkdtm: fix clang -Wformat warning
Date: Thu, 21 Jul 2022 15:05:09 -0700 [thread overview]
Message-ID: <YtnNlZYZCEVUiuaE@dev-arch.thelio-3990X> (raw)
In-Reply-To: <20220721215706.4153027-1-justinstitt@google.com>
On Thu, Jul 21, 2022 at 02:57:06PM -0700, Justin Stitt wrote:
> When building with Clang we encounter the following warning
> (ARCH=hexagon + CONFIG_FRAME_WARN=0):
> | ../drivers/misc/lkdtm/bugs.c:107:3: error: format specifies type
> | 'unsigned long' but the argument has type 'int' [-Werror,-Wformat]
> | REC_STACK_SIZE, recur_count);
> | ^~~~~~~~~~~~~~
>
> Cast REC_STACK_SIZE to `unsigned long` to match format specifier `%lu`
> as well as maintain symmetry with `#define REC_STACK_SIZE
> (_AC(CONFIG_FRAME_WARN, UL) / 2)`.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/378
> Reported-by: Nathan Chancellor <nathan@kernel.org>
> Suggested-by: Nathan Chancellor <nathan@kernel.org>
Personally, I would drop this; my suggestion was the cast, which we are
not going with anymore. Not worth a v3 unless there are other changes
requested.
> Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
> Signed-off-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
> ---
> Reported by Nathan here:
> https://lore.kernel.org/all/YtmrCJjQrSbv8Aj1@dev-arch.thelio-3990X/
>
> changes from v1 -> v2:
> * Use implicit division conversion with `/ nUL` instead of verbose
> `(unsigned long)` ~ Thanks Nick
>
> drivers/misc/lkdtm/bugs.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c
> index 009239ad1d8a..48821f4c2b21 100644
> --- a/drivers/misc/lkdtm/bugs.c
> +++ b/drivers/misc/lkdtm/bugs.c
> @@ -29,7 +29,7 @@ struct lkdtm_list {
> #if defined(CONFIG_FRAME_WARN) && (CONFIG_FRAME_WARN > 0)
> #define REC_STACK_SIZE (_AC(CONFIG_FRAME_WARN, UL) / 2)
> #else
> -#define REC_STACK_SIZE (THREAD_SIZE / 8)
> +#define REC_STACK_SIZE (THREAD_SIZE / 8UL)
> #endif
> #define REC_NUM_DEFAULT ((THREAD_SIZE / REC_STACK_SIZE) * 2)
>
> --
> 2.37.1.359.gd136c6c3e2-goog
>
>
next prev parent reply other threads:[~2022-07-21 22:05 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-21 21:20 [PATCH] " Justin Stitt
2022-07-21 21:34 ` Nathan Chancellor
2022-07-21 21:42 ` Nick Desaulniers
2022-07-21 21:57 ` [PATCH v2] " Justin Stitt
2022-07-21 22:05 ` Nathan Chancellor [this message]
2022-07-23 13:42 ` Kees Cook
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