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> --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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