drivers/pinctrl/bcm/pinctrl-bcm2835.c:412:14: warning: variable 'group' is used uninitialized whenever 'for' loop exits because its condition is false

From: kernel test robot
Date: Sat Nov 06 2021 - 08:12:16 EST

tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: fe91c4725aeed35023ba4f7a1e1adfebb6878c23
commit: 29d45a642d4ea8de7e89b57f856046df7c3b219f pinctrl: bcm2835: Replace BUG with BUG_ON
date: 4 months ago
config: mips-randconfig-c004-20211019 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project d245f2e8597bfb52c34810a328d42b990e4af1a4)
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/?id=29d45a642d4ea8de7e89b57f856046df7c3b219f
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 attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=mips

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

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

00445b5d5866c7 drivers/pinctrl/bcm/pinctrl-bcm2835.c Phil Elwell 2015-02-24 402
85ae9e512f437c drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 403 static void bcm2835_gpio_irq_handler(struct irq_desc *desc)
00445b5d5866c7 drivers/pinctrl/bcm/pinctrl-bcm2835.c Phil Elwell 2015-02-24 404 {
85ae9e512f437c drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 405 struct gpio_chip *chip = irq_desc_get_handler_data(desc);
85ae9e512f437c drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 406 struct bcm2835_pinctrl *pc = gpiochip_get_data(chip);
85ae9e512f437c drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 407 struct irq_chip *host_chip = irq_desc_get_chip(desc);
85ae9e512f437c drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 408 int irq = irq_desc_get_irq(desc);
85ae9e512f437c drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 409 int group;
85ae9e512f437c drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 410 int i;
85ae9e512f437c drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 411
73345a18d464b1 drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2019-08-12 @412 for (i = 0; i < BCM2835_NUM_IRQS; i++) {
73345a18d464b1 drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2019-08-12 413 if (chip->irq.parents[i] == irq) {
0d885e9da176ad drivers/pinctrl/bcm/pinctrl-bcm2835.c Thierry Reding 2017-07-20 414 group = i;
85ae9e512f437c drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 415 break;
85ae9e512f437c drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 416 }
85ae9e512f437c drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 417 }
85ae9e512f437c drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 418 /* This should not happen, every IRQ has a bank */
29d45a642d4ea8 drivers/pinctrl/bcm/pinctrl-bcm2835.c Jason Wang 2021-06-24 419 BUG_ON(i == BCM2835_NUM_IRQS);
00445b5d5866c7 drivers/pinctrl/bcm/pinctrl-bcm2835.c Phil Elwell 2015-02-24 420
85ae9e512f437c drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 421 chained_irq_enter(host_chip, desc);
85ae9e512f437c drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 422
85ae9e512f437c drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 423 switch (group) {
00445b5d5866c7 drivers/pinctrl/bcm/pinctrl-bcm2835.c Phil Elwell 2015-02-24 424 case 0: /* IRQ0 covers GPIOs 0-27 */
85ae9e512f437c drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 425 bcm2835_gpio_irq_handle_bank(pc, 0, 0x0fffffff);
00445b5d5866c7 drivers/pinctrl/bcm/pinctrl-bcm2835.c Phil Elwell 2015-02-24 426 break;
00445b5d5866c7 drivers/pinctrl/bcm/pinctrl-bcm2835.c Phil Elwell 2015-02-24 427 case 1: /* IRQ1 covers GPIOs 28-45 */
85ae9e512f437c drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 428 bcm2835_gpio_irq_handle_bank(pc, 0, 0xf0000000);
00445b5d5866c7 drivers/pinctrl/bcm/pinctrl-bcm2835.c Phil Elwell 2015-02-24 429 bcm2835_gpio_irq_handle_bank(pc, 1, 0x00003fff);
00445b5d5866c7 drivers/pinctrl/bcm/pinctrl-bcm2835.c Phil Elwell 2015-02-24 430 break;
b1d84a3d0a26c5 drivers/pinctrl/bcm/pinctrl-bcm2835.c Stefan Wahren 2020-02-08 431 case 2: /* IRQ2 covers GPIOs 46-57 */
85ae9e512f437c drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 432 bcm2835_gpio_irq_handle_bank(pc, 1, 0x003fc000);
00445b5d5866c7 drivers/pinctrl/bcm/pinctrl-bcm2835.c Phil Elwell 2015-02-24 433 break;
00445b5d5866c7 drivers/pinctrl/bcm/pinctrl-bcm2835.c Phil Elwell 2015-02-24 434 }
00445b5d5866c7 drivers/pinctrl/bcm/pinctrl-bcm2835.c Phil Elwell 2015-02-24 435
85ae9e512f437c drivers/pinctrl/bcm/pinctrl-bcm2835.c Linus Walleij 2016-11-14 436 chained_irq_exit(host_chip, desc);
e1b2dc70cd5b00 drivers/pinctrl/pinctrl-bcm2835.c Simon Arlott 2012-09-27 437 }
e1b2dc70cd5b00 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@xxxxxxxxxx>
:::::: CC: Linus Walleij <linus.walleij@xxxxxxxxxx>

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx

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