drivers/power/supply/qcom_pmi8998_charger.c:565 smb2_status_change_work() error: uninitialized symbol 'usb_online'.

drivers/power/supply/qcom_pmi8998_charger.c:565 smb2_status_change_work() error: uninitialized symbol 'usb_online'.

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   57012c57536f8814dec92e74197ee96c3498d24e
commit: 8648aeb5d7b70e13264ff5f444f22081d37d4670 power: supply: add Qualcomm PMI8998 SMB2 Charger driver
config: arm-randconfig-m041-20230727 (https://download.01.org/0day-ci/archive/20230728/202307280638.556PrzIS-lkp@intel.com/config)
compiler: arm-linux-gnueabi-gcc (GCC) 12.3.0
reproduce: (https://download.01.org/0day-ci/archive/20230728/202307280638.556PrzIS-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <error27@gmail.com>
| Closes: https://lore.kernel.org/r/202307280638.556PrzIS-lkp@intel.com/

smatch warnings:
drivers/power/supply/qcom_pmi8998_charger.c:565 smb2_status_change_work() error: uninitialized symbol 'usb_online'.

vim +/usb_online +565 drivers/power/supply/qcom_pmi8998_charger.c

8648aeb5d7b70e Caleb Connolly 2023-05-26  556  static void smb2_status_change_work(struct work_struct *work)
8648aeb5d7b70e Caleb Connolly 2023-05-26  557  {
8648aeb5d7b70e Caleb Connolly 2023-05-26  558  	unsigned int charger_type, current_ua;
8648aeb5d7b70e Caleb Connolly 2023-05-26  559  	int usb_online, count, rc;
8648aeb5d7b70e Caleb Connolly 2023-05-26  560  	struct smb2_chip *chip;
8648aeb5d7b70e Caleb Connolly 2023-05-26  561  
8648aeb5d7b70e Caleb Connolly 2023-05-26  562  	chip = container_of(work, struct smb2_chip, status_change_work.work);
8648aeb5d7b70e Caleb Connolly 2023-05-26  563  
8648aeb5d7b70e Caleb Connolly 2023-05-26  564  	smb2_get_prop_usb_online(chip, &usb_online);

This can only happen if regmap_read() fails, and in real life they
can't actually fail can they?  We can't really recover if regmap
breaks so in that situation this uninitialized variable would be the
least of our concerns.  Right?

So what I could do is just delete the regmap_read error paths from
the DB.  I just add these two lines to smatch_data/db/kernel.delete.return_states

regmap_read (-22)
regmap_read (-4095)-(-1)

8648aeb5d7b70e Caleb Connolly 2023-05-26 @565  	if (!usb_online)
                                                     ^^^^^^^^^^

8648aeb5d7b70e Caleb Connolly 2023-05-26  566  		return;
8648aeb5d7b70e Caleb Connolly 2023-05-26  567  
8648aeb5d7b70e Caleb Connolly 2023-05-26  568  	for (count = 0; count < 3; count++) {
8648aeb5d7b70e Caleb Connolly 2023-05-26  569  		dev_dbg(chip->dev, "get charger type retry %d\n", count);

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: drivers/power/supply/qcom_pmi8998_charger.c:565 smb2_status_change_work() error: uninitialized symbol 'usb_online'.

[Caleb Connolly]

On 28/07/2023 06:45, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   57012c57536f8814dec92e74197ee96c3498d24e
> commit: 8648aeb5d7b70e13264ff5f444f22081d37d4670 power: supply: add Qualcomm PMI8998 SMB2 Charger driver
> config: arm-randconfig-m041-20230727 (https://download.01.org/0day-ci/archive/20230728/202307280638.556PrzIS-lkp@intel.com/config)
> compiler: arm-linux-gnueabi-gcc (GCC) 12.3.0
> reproduce: (https://download.01.org/0day-ci/archive/20230728/202307280638.556PrzIS-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Reported-by: Dan Carpenter <error27@gmail.com>
> | Closes: https://lore.kernel.org/r/202307280638.556PrzIS-lkp@intel.com/
> 
> smatch warnings:
> drivers/power/supply/qcom_pmi8998_charger.c:565 smb2_status_change_work() error: uninitialized symbol 'usb_online'.

Hi, thanks for the report.
> 
> vim +/usb_online +565 drivers/power/supply/qcom_pmi8998_charger.c
> 
> 8648aeb5d7b70e Caleb Connolly 2023-05-26  556  static void smb2_status_change_work(struct work_struct *work)
> 8648aeb5d7b70e Caleb Connolly 2023-05-26  557  {
> 8648aeb5d7b70e Caleb Connolly 2023-05-26  558  	unsigned int charger_type, current_ua;
> 8648aeb5d7b70e Caleb Connolly 2023-05-26  559  	int usb_online, count, rc;
> 8648aeb5d7b70e Caleb Connolly 2023-05-26  560  	struct smb2_chip *chip;
> 8648aeb5d7b70e Caleb Connolly 2023-05-26  561  
> 8648aeb5d7b70e Caleb Connolly 2023-05-26  562  	chip = container_of(work, struct smb2_chip, status_change_work.work);
> 8648aeb5d7b70e Caleb Connolly 2023-05-26  563  
> 8648aeb5d7b70e Caleb Connolly 2023-05-26  564  	smb2_get_prop_usb_online(chip, &usb_online);
> 
> This can only happen if regmap_read() fails, and in real life they
> can't actually fail can they?  We can't really recover if regmap
> breaks so in that situation this uninitialized variable would be the
> least of our concerns.  Right?

In this case, the driver is for a peripheral on the SPMI bus, a read
failing is extremely unlikely but under some conditions like bandwidth
constraints it could happen. Though admittedly there are likely bigger
issues to deal with in that situation heh.

It's a trivial fix so I'll send a patch over.
> 
> So what I could do is just delete the regmap_read error paths from
> the DB.  I just add these two lines to smatch_data/db/kernel.delete.return_states
> 
> regmap_read (-22)
> regmap_read (-4095)-(-1)
> 
> 8648aeb5d7b70e Caleb Connolly 2023-05-26 @565  	if (!usb_online)
>                                                      ^^^^^^^^^^
> 
> 8648aeb5d7b70e Caleb Connolly 2023-05-26  566  		return;
> 8648aeb5d7b70e Caleb Connolly 2023-05-26  567  
> 8648aeb5d7b70e Caleb Connolly 2023-05-26  568  	for (count = 0; count < 3; count++) {
> 8648aeb5d7b70e Caleb Connolly 2023-05-26  569  		dev_dbg(chip->dev, "get charger type retry %d\n", count);
> 

-- 
// Caleb (they/them)