Re: [PATCH] timekeeping: contribute wall clock to rng on time change

[kernel test robot <lkp@intel.com>]

Hi "Jason,

I love your patch! Yet something to improve:

[auto build test ERROR on tip/timers/core]
[also build test ERROR on linus/master v5.19-rc3 next-20220623]
[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]

url:    https://github.com/intel-lab-lkp/linux/commits/Jason-A-Donenfeld/timekeeping-contribute-wall-clock-to-rng-on-time-change/20220624-010017
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git 57963a92a70b037aa22544fbc34742e5be689c04
config: i386-tinyconfig (https://download.01.org/0day-ci/archive/20220624/202206240128.jVs1F5jD-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.3.0-3) 11.3.0
reproduce (this is a W=1 build):
        # https://github.com/intel-lab-lkp/linux/commit/f2f11bc49b9a71c5663e44d46c8265f9b4fc8011
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Jason-A-Donenfeld/timekeeping-contribute-wall-clock-to-rng-on-time-change/20220624-010017
        git checkout f2f11bc49b9a71c5663e44d46c8265f9b4fc8011
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash kernel/time/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   kernel/time/timekeeping.c: In function 'do_settimeofday64':
>> kernel/time/timekeeping.c:1349:9: error: implicit declaration of function 'add_device_randomness' [-Werror=implicit-function-declaration]
    1349 |         add_device_randomness(&xt, sizeof(xt));
         |         ^~~~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +/add_device_randomness +1349 kernel/time/timekeeping.c

  1303	
  1304	/**
  1305	 * do_settimeofday64 - Sets the time of day.
  1306	 * @ts:     pointer to the timespec64 variable containing the new time
  1307	 *
  1308	 * Sets the time of day to the new time and update NTP and notify hrtimers
  1309	 */
  1310	int do_settimeofday64(const struct timespec64 *ts)
  1311	{
  1312		struct timekeeper *tk = &tk_core.timekeeper;
  1313		struct timespec64 ts_delta, xt;
  1314		unsigned long flags;
  1315		int ret = 0;
  1316	
  1317		if (!timespec64_valid_settod(ts))
  1318			return -EINVAL;
  1319	
  1320		raw_spin_lock_irqsave(&timekeeper_lock, flags);
  1321		write_seqcount_begin(&tk_core.seq);
  1322	
  1323		timekeeping_forward_now(tk);
  1324	
  1325		xt = tk_xtime(tk);
  1326		ts_delta = timespec64_sub(*ts, xt);
  1327	
  1328		if (timespec64_compare(&tk->wall_to_monotonic, &ts_delta) > 0) {
  1329			ret = -EINVAL;
  1330			goto out;
  1331		}
  1332	
  1333		tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta));
  1334	
  1335		tk_set_xtime(tk, ts);
  1336	out:
  1337		timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
  1338	
  1339		write_seqcount_end(&tk_core.seq);
  1340		raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
  1341	
  1342		/* Signal hrtimers about time change */
  1343		clock_was_set(CLOCK_SET_WALL);
  1344	
  1345		if (!ret)
  1346			audit_tk_injoffset(ts_delta);
  1347	
  1348		ktime_get_real_ts64(&xt);
> 1349		add_device_randomness(&xt, sizeof(xt));
  1350	
  1351		return ret;
  1352	}
  1353	EXPORT_SYMBOL(do_settimeofday64);
  1354	

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