| Message ID | 20190307103219.1539316-1-arnd@arndb.de |
|---|---|
| State | Accepted |
| Commit | a2ae6da025ed73e4312d983b5e57300bc77090f3 |
| Headers | show |
| Series | peak_usb: fix clang build warning | expand |
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 >
On Thu, Mar 7, 2019 at 4:31 PM Nathan Chancellor <natechancellor@gmail.com> wrote: > > 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> Thanks! > I wonder if the format specifier in the pr_err statement at the end of > this function should be updated. I think it's still ok as it is. Arnd
From: Arnd Bergmann <arnd@arndb.de> Date: Thu, 7 Mar 2019 11:31:55 +0100 > 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> Applied.
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;
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> --- drivers/net/can/usb/peak_usb/pcan_usb_pro.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- 2.20.0