Hi Steve, FYI, the error/warning still remains. tree: https://android.googlesource.com/kernel/common android11-5.4 head: bf4d02ab1ecad898c38734f26b71ace90293c588 commit: 5f378fd56aa3988be21e859254a2d72628d044c6 [3942/13266] ANDROID: rtc: class: support hctosys from modular RTC drivers config: i386-randconfig-r013-20210816 (attached as .config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): git remote add android-common https://android.googlesource.com/kernel/common git fetch --no-tags android-common android11-5.4 git checkout 5f378fd56aa3988be21e859254a2d72628d044c6 # save the attached .config to linux build tree make W=1 ARCH=i386 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): 24 | int rtc_hctosys(void) | ^~~~~~~~~~~ vim +/rtc_hctosys +24 drivers/rtc/hctosys.c 12 13 /* IMPORTANT: the RTC only stores whole seconds. It is arbitrary 14 * whether it stores the most close value or the value with partial 15 * seconds truncated. However, it is important that we use it to store 16 * the truncated value. This is because otherwise it is necessary, 17 * in an rtc sync function, to read both xtime.tv_sec and 18 * xtime.tv_nsec. On some processors (i.e. ARM), an atomic read 19 * of >32bits is not possible. So storing the most close value would 20 * slow down the sync API. So here we have the truncated value and 21 * the best guess is to add 0.5s. 22 */ 23 25 { 26 int err = -ENODEV; 27 struct rtc_time tm; 28 struct timespec64 tv64 = { 29 .tv_nsec = NSEC_PER_SEC >> 1, 30 }; 31 struct rtc_device *rtc = rtc_class_open(CONFIG_RTC_HCTOSYS_DEVICE); 32 33 if (!rtc) { 34 pr_info("unable to open rtc device (%s)\n", 35 CONFIG_RTC_HCTOSYS_DEVICE); 36 goto err_open; 37 } 38 39 err = rtc_read_time(rtc, &tm); 40 if (err) { 41 dev_err(rtc->dev.parent, 42 "hctosys: unable to read the hardware clock\n"); 43 goto err_read; 44 } 45 46 tv64.tv_sec = rtc_tm_to_time64(&tm); 47 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org