Re: [PATCH] ntp: Make sure RTC is synchronized when time goes backwards

[kernel test robot]

Hi Benjamin,

kernel test robot noticed the following build errors:

[auto build test ERROR on tip/timers/core]
[also build test ERROR on linus/master v6.11-rc6 next-20240906]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Benjamin-ROBIN/ntp-Make-sure-RTC-is-synchronized-when-time-goes-backwards/20240908-032754
base:   tip/timers/core
patch link:    https://lore.kernel.org/r/20240907190900.55421-1-dev%40benjarobin.fr
patch subject: [PATCH] ntp: Make sure RTC is synchronized when time goes backwards
config: arm-randconfig-r071-20240908 (https://download.01.org/0day-ci/archive/20240908/202409082049.yA7d6Zmw-lkp@xxxxxxxxx/config)
compiler: clang version 20.0.0git (https://github.com/llvm/llvm-project 05f5a91d00b02f4369f46d076411c700755ae041)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240908/202409082049.yA7d6Zmw-lkp@xxxxxxxxx/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@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202409082049.yA7d6Zmw-lkp@xxxxxxxxx/

All errors (new ones prefixed by >>):

   In file included from kernel/time/ntp.c:17:
   In file included from include/linux/mm.h:2228:
   include/linux/vmstat.h:514:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
     514 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
         |                               ~~~~~~~~~~~ ^ ~~~
>> kernel/time/ntp.c:757:19: error: use of undeclared identifier 'sync_hrtimer'
     757 |                 hrtimer_cancel(&sync_hrtimer);
         |                                 ^
   1 warning and 1 error generated.


vim +/sync_hrtimer +757 kernel/time/ntp.c

   707	
   708	
   709	static inline void process_adjtimex_modes(const struct __kernel_timex *txc,
   710						  s32 *time_tai)
   711	{
   712		if (txc->modes & ADJ_STATUS)
   713			process_adj_status(txc);
   714	
   715		if (txc->modes & ADJ_NANO)
   716			time_status |= STA_NANO;
   717	
   718		if (txc->modes & ADJ_MICRO)
   719			time_status &= ~STA_NANO;
   720	
   721		if (txc->modes & ADJ_FREQUENCY) {
   722			time_freq = txc->freq * PPM_SCALE;
   723			time_freq = min(time_freq, MAXFREQ_SCALED);
   724			time_freq = max(time_freq, -MAXFREQ_SCALED);
   725			/* update pps_freq */
   726			pps_set_freq(time_freq);
   727		}
   728	
   729		if (txc->modes & ADJ_MAXERROR)
   730			time_maxerror = txc->maxerror;
   731	
   732		if (txc->modes & ADJ_ESTERROR)
   733			time_esterror = txc->esterror;
   734	
   735		if (txc->modes & ADJ_TIMECONST) {
   736			time_constant = txc->constant;
   737			if (!(time_status & STA_NANO))
   738				time_constant += 4;
   739			time_constant = min(time_constant, (long)MAXTC);
   740			time_constant = max(time_constant, 0l);
   741		}
   742	
   743		if (txc->modes & ADJ_TAI &&
   744				txc->constant >= 0 && txc->constant <= MAX_TAI_OFFSET)
   745			*time_tai = txc->constant;
   746	
   747		if (txc->modes & ADJ_OFFSET)
   748			ntp_update_offset(txc->offset);
   749	
   750		if (txc->modes & ADJ_TICK)
   751			tick_usec = txc->tick;
   752	
   753		if (txc->modes & (ADJ_TICK|ADJ_FREQUENCY|ADJ_OFFSET))
   754			ntp_update_frequency();
   755	
   756		if (txc->modes & ADJ_SETOFFSET)
 > 757			hrtimer_cancel(&sync_hrtimer);
   758	}
   759	

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