[rcu:dev.2020.06.02a 85/90] kernel/smp.c:122: undefined reference to `__udivdi3'

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

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tree:   https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev.2020.06.02a
head:   5216948905dd07a84cef8a7dc72c2ec076802efd
commit: 92ebbb71443dced2019cd24b737ce60b03a29e10 [85/90] EXP kernel/smp: Provide CSD lock timeout diagnostics
config: i386-randconfig-c001-20200605 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-13) 9.3.0

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

All errors (new ones prefixed by >>, old ones prefixed by <<):

ld: kernel/smp.o: in function `csd_lock_wait':
>> kernel/smp.c:122: undefined reference to `__udivdi3'
>> ld: kernel/smp.c:128: undefined reference to `__udivdi3'
>> ld: kernel/smp.c:136: undefined reference to `__umoddi3'
ld: kernel/smp.c:136: undefined reference to `__udivdi3'
>> ld: kernel/smp.c:122: undefined reference to `__udivdi3'
>> ld: kernel/smp.c:128: undefined reference to `__udivdi3'
>> ld: kernel/smp.c:136: undefined reference to `__umoddi3'
ld: kernel/smp.c:136: undefined reference to `__udivdi3'
>> ld: kernel/smp.c:122: undefined reference to `__udivdi3'
>> ld: kernel/smp.c:128: undefined reference to `__udivdi3'
>> ld: kernel/smp.c:136: undefined reference to `__umoddi3'
ld: kernel/smp.c:136: undefined reference to `__udivdi3'
>> ld: kernel/smp.c:122: undefined reference to `__udivdi3'
>> ld: kernel/smp.c:128: undefined reference to `__udivdi3'
>> ld: kernel/smp.c:136: undefined reference to `__umoddi3'
ld: kernel/smp.c:136: undefined reference to `__udivdi3'

vim +122 kernel/smp.c

   107	
   108	/*
   109	 * csd_lock/csd_unlock used to serialize access to per-cpu csd resources
   110	 *
   111	 * For non-synchronous ipi calls the csd can still be in use by the
   112	 * previous function call. For multi-cpu calls its even more interesting
   113	 * as we'll have to ensure no other cpu is observing our csd.
   114	 */
   115	static __always_inline void csd_lock_wait(call_single_data_t *csd)
   116	{
   117		int bug_id = 0;
   118		int cpu;
   119		call_single_data_t *cpu_cur_csd;
   120		u64 ts0, ts1, ts2, ts_delta;
   121	
 > 122		ts1 = ts0 = sched_clock() / 1000 / 1000;
   123		for (;;) {
   124			unsigned long flags = READ_ONCE(csd->flags);
   125	
   126			if (!(flags & CSD_FLAG_LOCK))
   127				break;
 > 128			ts2 = sched_clock() / 1000 / 1000;
   129			ts_delta = ts2 - ts1;
   130			if (unlikely(ts_delta > CSD_LOCK_TIMEOUT)) {
   131				bug_id = atomic_inc_return(&csd_bug_count);
   132				cpu = csd->cpu;
   133				smp_mb(); // No stale cur_csd values!
   134				cpu_cur_csd = per_cpu(cur_csd, cpu);
   135				smp_mb(); // No refetching cur_csd values!
 > 136				printk("csd: Detected non-responsive CSD lock (#%d) on CPU#%d, waiting %Ld.%03Ld secs for CPU#%02d %pf(%ps), currently %s.\n",
   137				       bug_id, raw_smp_processor_id(),
   138				       ts_delta/1000ULL, ts_delta % 1000ULL, cpu,
   139				       csd->func, csd->info,
   140				       !cpu_cur_csd ? "unresponsive"
   141						: csd == cpu_cur_csd
   142							? "handling this request"
   143							: "handling prior request");
   144				if (!trigger_single_cpu_backtrace(cpu))
   145					dump_cpu_task(cpu);
   146				if (!cpu_cur_csd) {
   147					printk("csd: Re-sending CSD lock (#%d) IPI from CPU#%02d to CPU#%02d\n", bug_id, raw_smp_processor_id(), cpu);
   148					arch_send_call_function_single_ipi(cpu);
   149				}
   150				dump_stack();
   151				ts1 = ts2;
   152			}
   153			cpu_relax();
   154		}
   155		smp_acquire__after_ctrl_dep();
   156		if (unlikely(bug_id))
   157			printk("csd: CSD lock (#%d) got unstuck on CPU#%02d, CPU#%02d released the lock after all. Phew!\n", bug_id, raw_smp_processor_id(), cpu);
   158	}
   159	

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