Re: [PATCH v5 2/4] kernel hacking: new config NO_AUTO_INLINE to disable compiler auto-inline optimizations

[kbuild test robot]

Hi Changbin,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v4.17-rc5 next-20180517]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/changbin-du-intel-com/kernel-hacking-GCC-optimization-for-better-debug-experience-Og/20180512-001150
config: sparc64-allyesconfig (attached as .config)
compiler: sparc64-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=sparc64 

Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings

All warnings (new ones prefixed by >>):

   drivers//staging/comedi/drivers/pcl816.c: In function 'pcl816_ai_setup_chanlist':
>> drivers//staging/comedi/drivers/pcl816.c:171:2: warning: 'last_chan' may be used uninitialized in this function [-Wmaybe-uninitialized]
     pcl816_ai_set_chan_scan(dev, first_chan, last_chan);
     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
--
   drivers//staging/comedi/drivers/pcl818.c: In function 'pcl818_ai_setup_chanlist':
>> drivers//staging/comedi/drivers/pcl818.c:366:2: warning: 'last_chan' may be used uninitialized in this function [-Wmaybe-uninitialized]
     pcl818_ai_set_chan_scan(dev, first_chan, last_chan);
     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
--
   drivers/net/wireless/ath/ath10k/mac.c: In function 'ath10k_mac_init_rd':
>> drivers/net/wireless/ath/ath10k/mac.c:8172:39: warning: 'rd' may be used uninitialized in this function [-Wmaybe-uninitialized]
     ar->ath_common.regulatory.current_rd = rd;
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
--
   drivers/dma/stm32-mdma.c: In function 'stm32_mdma_setup_xfer':
>> drivers/dma/stm32-mdma.c:767:6: warning: 'ccr' may be used uninitialized in this function [-Wmaybe-uninitialized]
     ccr &= ~STM32_MDMA_CCR_IRQ_MASK;
         ^~
--
   drivers/gpio/gpio-aspeed.c: In function 'enable_debounce':
>> drivers/gpio/gpio-aspeed.c:708:6: warning: 'requested_cycles' may be used uninitialized in this function [-Wmaybe-uninitialized]
      if (requested_cycles == cycles)
         ^
--
   drivers/mmc/host/sdhci-pci-core.c: In function 'intel_dsm_init.isra.3':
>> drivers/mmc/host/sdhci-pci-core.c:527:37: warning: 'val' may be used uninitialized in this function [-Wmaybe-uninitialized]
     intel_host->d3_retune = err ? true : !!val;
                             ~~~~~~~~~~~^~~~~~~

vim +/last_chan +171 drivers//staging/comedi/drivers/pcl816.c

19720c07 H Hartley Sweeten 2014-03-04  151  
19720c07 H Hartley Sweeten 2014-03-04  152  static void pcl816_ai_setup_chanlist(struct comedi_device *dev,
19720c07 H Hartley Sweeten 2014-03-04  153  				     unsigned int *chanlist,
19720c07 H Hartley Sweeten 2014-03-04  154  				     unsigned int seglen)
19720c07 H Hartley Sweeten 2014-03-04  155  {
19720c07 H Hartley Sweeten 2014-03-04  156  	unsigned int first_chan = CR_CHAN(chanlist[0]);
19720c07 H Hartley Sweeten 2014-03-04  157  	unsigned int last_chan;
19720c07 H Hartley Sweeten 2014-03-04  158  	unsigned int range;
19720c07 H Hartley Sweeten 2014-03-04  159  	unsigned int i;
19720c07 H Hartley Sweeten 2014-03-04  160  
19720c07 H Hartley Sweeten 2014-03-04  161  	/* store range list to card */
19720c07 H Hartley Sweeten 2014-03-04  162  	for (i = 0; i < seglen; i++) {
19720c07 H Hartley Sweeten 2014-03-04  163  		last_chan = CR_CHAN(chanlist[i]);
19720c07 H Hartley Sweeten 2014-03-04  164  		range = CR_RANGE(chanlist[i]);
19720c07 H Hartley Sweeten 2014-03-04  165  
19720c07 H Hartley Sweeten 2014-03-04  166  		pcl816_ai_set_chan_range(dev, last_chan, range);
19720c07 H Hartley Sweeten 2014-03-04  167  	}
19720c07 H Hartley Sweeten 2014-03-04  168  
19720c07 H Hartley Sweeten 2014-03-04  169  	udelay(1);
19720c07 H Hartley Sweeten 2014-03-04  170  
19720c07 H Hartley Sweeten 2014-03-04 @171  	pcl816_ai_set_chan_scan(dev, first_chan, last_chan);
19720c07 H Hartley Sweeten 2014-03-04  172  }
19720c07 H Hartley Sweeten 2014-03-04  173  

:::::: The code at line 171 was first introduced by commit
:::::: 19720c07f1f82c21311f3f7ac3e9b993598d6b70 staging: comedi: pcl816: cleanup setup_channel_list()

:::::: TO: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
:::::: CC: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

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0-DAY kernel test infrastructure                Open Source Technology Center
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