drivers/pinctrl/bcm/pinctrl-bcm2835.c:412:14: warning: variable 'group' is used uninitialized whenever 'for' loop exits because its condition is false
1:44 a.m.
Hi Jason,
FYI, the error/warning still remains.
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 5472f14a37421d1bca3dddf33cabd3bd6dbefbbc
commit: 29d45a642d4ea8de7e89b57f856046df7c3b219f pinctrl: bcm2835: Replace BUG with
BUG_ON
date: 5 months ago
config: mips-randconfig-c004-20211214
(https://download.01.org/0day-ci/archive/20211214/202112142208.QW0tVv0m-lk...)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project
b6a2ddb6c8ac29412b1361810972e15221fa021c)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O
~/bin/make.cross
chmod +x ~/bin/make.cross
# install mips cross compiling tool for clang build
# apt-get install binutils-mips-linux-gnu
#
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit...
git remote add linus
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout 29d45a642d4ea8de7e89b57f856046df7c3b219f
# save the config file to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir
ARCH=mips SHELL=/bin/bash drivers/pinctrl/bcm/
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp(a)intel.com>
All warnings (new ones prefixed by >>):
> drivers/pinctrl/bcm/pinctrl-bcm2835.c:412:14: warning: variable
'group' is used uninitialized whenever 'for' loop exits because its
condition is false [-Wsometimes-uninitialized]
for (i = 0; i <
BCM2835_NUM_IRQS; i++) {
^~~~~~~~~~~~~~~~~~~~
drivers/pinctrl/bcm/pinctrl-bcm2835.c:423:10: note: uninitialized use occurs here
switch (group) {
^~~~~
drivers/pinctrl/bcm/pinctrl-bcm2835.c:412:14: note: remove the condition if it is
always true
for (i = 0; i < BCM2835_NUM_IRQS; i++) {
^~~~~~~~~~~~~~~~~~~~
drivers/pinctrl/bcm/pinctrl-bcm2835.c:409:11: note: initialize the variable
'group' to silence this warning
int group;
^
= 0
1 warning generated.
vim +412 drivers/pinctrl/bcm/pinctrl-bcm2835.c
00445b5d5866c7b drivers/pinctrl/bcm/pinctrl-bcm2835.c Phil Elwell 2015-02-24 402
85ae9e512f437cd drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 403
static void bcm2835_gpio_irq_handler(struct irq_desc *desc)
00445b5d5866c7b drivers/pinctrl/bcm/pinctrl-bcm2835.c Phil Elwell 2015-02-24 404 {
85ae9e512f437cd drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 405
struct gpio_chip *chip = irq_desc_get_handler_data(desc);
85ae9e512f437cd drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 406
struct bcm2835_pinctrl *pc = gpiochip_get_data(chip);
85ae9e512f437cd drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 407
struct irq_chip *host_chip = irq_desc_get_chip(desc);
85ae9e512f437cd drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 408 int
irq = irq_desc_get_irq(desc);
85ae9e512f437cd drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 409 int
group;
85ae9e512f437cd drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 410 int
i;
85ae9e512f437cd drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 411
73345a18d464b1b drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2019-08-12 @412 for
(i = 0; i < BCM2835_NUM_IRQS; i++) {
73345a18d464b1b drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2019-08-12 413 if
(chip->irq.parents[i] == irq) {
0d885e9da176ad3 drivers/pinctrl/bcm/pinctrl-bcm2835.c Thierry Reding 2017-07-20 414
group = i;
85ae9e512f437cd drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 415
break;
85ae9e512f437cd drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 416 }
85ae9e512f437cd drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 417 }
85ae9e512f437cd drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 418 /*
This should not happen, every IRQ has a bank */
29d45a642d4ea8d drivers/pinctrl/bcm/pinctrl-bcm2835.c Jason Wang 2021-06-24 419
BUG_ON(i == BCM2835_NUM_IRQS);
00445b5d5866c7b drivers/pinctrl/bcm/pinctrl-bcm2835.c Phil Elwell 2015-02-24 420
85ae9e512f437cd drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 421
chained_irq_enter(host_chip, desc);
85ae9e512f437cd drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 422
85ae9e512f437cd drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 423
switch (group) {
00445b5d5866c7b drivers/pinctrl/bcm/pinctrl-bcm2835.c Phil Elwell 2015-02-24 424
case 0: /* IRQ0 covers GPIOs 0-27 */
85ae9e512f437cd drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 425
bcm2835_gpio_irq_handle_bank(pc, 0, 0x0fffffff);
00445b5d5866c7b drivers/pinctrl/bcm/pinctrl-bcm2835.c Phil Elwell 2015-02-24 426
break;
00445b5d5866c7b drivers/pinctrl/bcm/pinctrl-bcm2835.c Phil Elwell 2015-02-24 427
case 1: /* IRQ1 covers GPIOs 28-45 */
85ae9e512f437cd drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 428
bcm2835_gpio_irq_handle_bank(pc, 0, 0xf0000000);
00445b5d5866c7b drivers/pinctrl/bcm/pinctrl-bcm2835.c Phil Elwell 2015-02-24 429
bcm2835_gpio_irq_handle_bank(pc, 1, 0x00003fff);
00445b5d5866c7b drivers/pinctrl/bcm/pinctrl-bcm2835.c Phil Elwell 2015-02-24 430
break;
b1d84a3d0a26c58 drivers/pinctrl/bcm/pinctrl-bcm2835.c Stefan Wahren 2020-02-08 431
case 2: /* IRQ2 covers GPIOs 46-57 */
85ae9e512f437cd drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 432
bcm2835_gpio_irq_handle_bank(pc, 1, 0x003fc000);
00445b5d5866c7b drivers/pinctrl/bcm/pinctrl-bcm2835.c Phil Elwell 2015-02-24 433
break;
00445b5d5866c7b drivers/pinctrl/bcm/pinctrl-bcm2835.c Phil Elwell 2015-02-24 434 }
00445b5d5866c7b drivers/pinctrl/bcm/pinctrl-bcm2835.c Phil Elwell 2015-02-24 435
85ae9e512f437cd drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 436
chained_irq_exit(host_chip, desc);
e1b2dc70cd5b00e drivers/pinctrl/pinctrl-bcm2835.c Simon Arlott 2012-09-27 437 }
e1b2dc70cd5b00e drivers/pinctrl/pinctrl-bcm2835.c Simon Arlott 2012-09-27 438
:::::: The code at line 412 was first introduced by commit
:::::: 73345a18d464b1b945b29f54f630ace6873344e2 pinctrl: bcm2835: Pass irqchip when adding
gpiochip
:::::: TO: Linus Walleij <linus.walleij(a)linaro.org>
:::::: CC: Linus Walleij <linus.walleij(a)linaro.org>
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
5:41 a.m.
On Tue, Dec 14, 2021 at 10:44:28PM +0800, kernel test robot wrote:
Hi Jason,
FYI, the error/warning still remains.
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 5472f14a37421d1bca3dddf33cabd3bd6dbefbbc
commit: 29d45a642d4ea8de7e89b57f856046df7c3b219f pinctrl: bcm2835: Replace BUG with
BUG_ON
date: 5 months ago
config: mips-randconfig-c004-20211214
(https://download.01.org/0day-ci/archive/20211214/202112142208.QW0tVv0m-lk...)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project
b6a2ddb6c8ac29412b1361810972e15221fa021c)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O
~/bin/make.cross
chmod +x ~/bin/make.cross
# install mips cross compiling tool for clang build
# apt-get install binutils-mips-linux-gnu
#
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit...
git remote add linus
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout 29d45a642d4ea8de7e89b57f856046df7c3b219f
# save the config file to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir
ARCH=mips SHELL=/bin/bash drivers/pinctrl/bcm/
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp(a)intel.com>
All warnings (new ones prefixed by >>):
>> drivers/pinctrl/bcm/pinctrl-bcm2835.c:412:14: warning: variable 'group'
is used uninitialized whenever 'for' loop exits because its condition is false
[-Wsometimes-uninitialized]
for (i = 0; i < BCM2835_NUM_IRQS; i++) {
^~~~~~~~~~~~~~~~~~~~
drivers/pinctrl/bcm/pinctrl-bcm2835.c:423:10: note: uninitialized use occurs here
switch (group) {
^~~~~
drivers/pinctrl/bcm/pinctrl-bcm2835.c:412:14: note: remove the condition if it is
always true
for (i = 0; i < BCM2835_NUM_IRQS; i++) {
^~~~~~~~~~~~~~~~~~~~
drivers/pinctrl/bcm/pinctrl-bcm2835.c:409:11: note: initialize the variable
'group' to silence this warning
int group;
^
= 0
1 warning generated.
It seems like MIP's __BUG_ON() makes it harder for clang to figure out
that 'i == BCM2835_NUM_IRQS' will make the kernel panic, which is the
only way that the loop exits because the condition is false.
I am not really sure of a way to fix this other than just reverting that
change or changing the BUG_ON() to WARN_ON().
Cheers,
Nathan
2:12 p.m.
On Tue, Dec 14, 2021 at 7:41 PM Nathan Chancellor <nathan(a)kernel.org> wrote:
On Tue, Dec 14, 2021 at 10:44:28PM +0800, kernel test robot wrote:
> Hi Jason,
>
> FYI, the error/warning still remains.
>
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head: 5472f14a37421d1bca3dddf33cabd3bd6dbefbbc
> commit: 29d45a642d4ea8de7e89b57f856046df7c3b219f pinctrl: bcm2835: Replace BUG with
BUG_ON
> date: 5 months ago
> config: mips-randconfig-c004-20211214
(https://download.01.org/0day-ci/archive/20211214/202112142208.QW0tVv0m-lk...)
> compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project
b6a2ddb6c8ac29412b1361810972e15221fa021c)
> reproduce (this is a W=1 build):
> wget
https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O
~/bin/make.cross
> chmod +x ~/bin/make.cross
> # install mips cross compiling tool for clang build
> # apt-get install binutils-mips-linux-gnu
> #
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit...
> git remote add linus
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> git fetch --no-tags linus master
> git checkout 29d45a642d4ea8de7e89b57f856046df7c3b219f
> # save the config file to linux build tree
> mkdir build_dir
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir
ARCH=mips SHELL=/bin/bash drivers/pinctrl/bcm/
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp(a)intel.com>
>
> All warnings (new ones prefixed by >>):
>
> >> drivers/pinctrl/bcm/pinctrl-bcm2835.c:412:14: warning: variable
'group' is used uninitialized whenever 'for' loop exits because its
condition is false [-Wsometimes-uninitialized]
> for (i = 0; i < BCM2835_NUM_IRQS; i++) {
> ^~~~~~~~~~~~~~~~~~~~
> drivers/pinctrl/bcm/pinctrl-bcm2835.c:423:10: note: uninitialized use occurs
here
> switch (group) {
> ^~~~~
> drivers/pinctrl/bcm/pinctrl-bcm2835.c:412:14: note: remove the condition if it is
always true
> for (i = 0; i < BCM2835_NUM_IRQS; i++) {
> ^~~~~~~~~~~~~~~~~~~~
> drivers/pinctrl/bcm/pinctrl-bcm2835.c:409:11: note: initialize the variable
'group' to silence this warning
> int group;
> ^
> = 0
> 1 warning generated.
It seems like MIP's __BUG_ON() makes it harder for clang to figure out
that 'i == BCM2835_NUM_IRQS' will make the kernel panic, which is the
only way that the loop exits because the condition is false.
I am not really sure of a way to fix this other than just reverting that
change or changing the BUG_ON() to WARN_ON().
We can also just ignore the test robot like any invalid
review comment.
The maintainer of this driver can decide, if it's up to me I'd
just ignore it.
Yours,
Linus Walleij
278
days inactive
280
days old
2 comments
3 participants
participants (3)
-
kernel test robot -
Linus Walleij -
Nathan Chancellor