From: Nathan Chancellor <natechancellor@gmail.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Wolfgang Grandegger <wg@grandegger.com>,
Marc Kleine-Budde <mkl@pengutronix.de>,
"David S. Miller" <davem@davemloft.net>,
Nick Desaulniers <ndesaulniers@google.com>,
"Gustavo A. R. Silva" <gustavo@embeddedor.com>,
linux-can@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] peak_usb: fix clang build warning
Date: Thu, 7 Mar 2019 08:31:43 -0700 [thread overview]
Message-ID: <20190307153143.GI20201@archlinux-ryzen> (raw)
In-Reply-To: <20190307103219.1539316-1-arnd@arndb.de>
On Thu, Mar 07, 2019 at 11:31:55AM +0100, Arnd Bergmann wrote:
> Clang points out undefined behavior when building the pcan_usb_pro driver:
>
> drivers/net/can/usb/peak_usb/pcan_usb_pro.c:136:15: error: passing an object that undergoes default argument promotion to 'va_start' has undefined behavior [-Werror,-Wvarargs]
>
> Changing the function prototype to avoid argument promotion in the
> varargs call avoids the warning, and should make this well-defined.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://github.com/ClangBuiltLinux/linux/issues/109
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
I wonder if the format specifier in the pr_err statement at the end of
this function should be updated.
> ---
> drivers/net/can/usb/peak_usb/pcan_usb_pro.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/can/usb/peak_usb/pcan_usb_pro.c b/drivers/net/can/usb/peak_usb/pcan_usb_pro.c
> index d516def846ab..b388406ac0f5 100644
> --- a/drivers/net/can/usb/peak_usb/pcan_usb_pro.c
> +++ b/drivers/net/can/usb/peak_usb/pcan_usb_pro.c
> @@ -127,7 +127,7 @@ static u8 *pcan_msg_init_empty(struct pcan_usb_pro_msg *pm,
> /*
> * add one record to a message being built
> */
> -static int pcan_msg_add_rec(struct pcan_usb_pro_msg *pm, u8 id, ...)
> +static int pcan_msg_add_rec(struct pcan_usb_pro_msg *pm, int id, ...)
> {
> int len, i;
> u8 *pc;
> --
> 2.20.0
>
next prev parent reply other threads:[~2019-03-07 15:31 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-07 10:31 [PATCH] peak_usb: fix clang build warning Arnd Bergmann
2019-03-07 15:31 ` Nathan Chancellor [this message]
2019-03-07 15:38 ` Arnd Bergmann
2019-03-07 17:40 ` David Miller
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