[thomas-weissschuh:b4/auxclock-nanosleep 41/41] kernel/time/timekeeping.c:185:36: warning: overflow in expression; result is 568'041'472 with type 'long'

[thomas-weissschuh:b4/auxclock-nanosleep 41/41] kernel/time/timekeeping.c:185:36: warning: overflow in expression; result is 568'041'472 with type 'long'

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/thomas.weissschuh/linux.git b4/auxclock-nanosleep
head:   87c2db12ba44bf5bea44868e32bd8df048af5586
commit: 87c2db12ba44bf5bea44868e32bd8df048af5586 [41/41] reciprocal
config: hexagon-allmodconfig (https://download.01.org/0day-ci/archive/20260827/202608271347.XtVtsxLQ-lkp@intel.com/config)
compiler: clang version 24.0.0git (https://github.com/llvm/llvm-project a908adb93db53c0d630232a5bdab8817495c17eb)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260827/202608271347.XtVtsxLQ-lkp@intel.com/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@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202608271347.XtVtsxLQ-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> kernel/time/timekeeping.c:185:36: warning: overflow in expression; result is 568'041'472 with type 'long' [-Winteger-overflow]
     185 |         this_delta = clamp(this_delta, 0, TK_AUX_MONO_CONV_MAX_DELTA_NS);
         |                      ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   kernel/time/timekeeping.c:148:45: note: expanded from macro 'TK_AUX_MONO_CONV_MAX_DELTA_NS'
     148 | #define TK_AUX_MONO_CONV_MAX_DELTA_NS           (400 * NSEC_PER_SEC)
         |                                                      ^
   include/linux/minmax.h:206:59: note: expanded from macro 'clamp'
     206 | #define clamp(val, lo, hi) __careful_clamp(auto, val, lo, hi)
         |                            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
   include/linux/minmax.h:195:30: note: expanded from macro '__careful_clamp'
     195 |         __clamp_once(type, val, lo, hi, __UNIQUE_ID(v_), __UNIQUE_ID(l_), __UNIQUE_ID(h_))
         |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:187:14: note: expanded from macro '__clamp_once'
     187 |         type uhi = (hi);                                                        \
         |                     ^~
   kernel/time/timekeeping.c:234:54: warning: overflow in expression; result is -647'710'720 with type 'long' [-Winteger-overflow]
     234 |         return ktime_sub(mono_now, mono_conv->mono_base) >= TK_AUX_MONO_CONV_FORCE_UPDATE_DELTA_NS;
         |                                                             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   kernel/time/timekeeping.c:149:53: note: expanded from macro 'TK_AUX_MONO_CONV_FORCE_UPDATE_DELTA_NS'
     149 | #define TK_AUX_MONO_CONV_FORCE_UPDATE_DELTA_NS  (300 * NSEC_PER_SEC)
         |                                                  ~~~~^~~~~~~~~~~~~~
   kernel/time/timekeeping.c:2291:13: warning: variable 'suspend_timing_needed' set but not used [-Wunused-but-set-global]
    2291 | static bool suspend_timing_needed;
         |             ^
   3 warnings generated.


vim +185 kernel/time/timekeeping.c

   175	
   176	static ktime_t ktime_mono_from_to_aux(ktime_t this_now, ktime_t this_base, ktime_t other_base,
   177					      u32 conv_mult)
   178	{
   179		ktime_t this_delta, other_delta;
   180	
   181		/* Both operands are guaranteed to be positive, no over- or underflow is possible. */
   182		this_delta = ktime_sub(this_now, this_base);
   183	
   184		/* Only values in this range can be converted without overflow. */
 > 185		this_delta = clamp(this_delta, 0, TK_AUX_MONO_CONV_MAX_DELTA_NS);
   186	
   187		other_delta = (this_delta * conv_mult) >> TK_AUX_MONO_CONV_SHIFT;
   188	
   189		/*
   190		 * Underflow is impossible, as other_base is always positive.
   191		 * Overflow is impossible, as other_base will never become big enough.
   192		 */
   193		return ktime_add(other_base, other_delta);
   194	}
   195	

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