[kbuild-all] Re: [peterz-queue:sched/core 4/9] arch/x86/kernel/smpboot.c:2083: undefined reference to `__udivdi3'

On Mon, 2020-05-18 at 11:35 +0200, Peter Zijlstra wrote: > On Sat, May 16, 2020 at 06:11:20AM +0800, kbuild test robot wrote: > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git sched/core > > head: 073d35d51f30267ccb43479be42d382f9b03fd9a > > commit: df24fd8a5838c3e24dc7a41b37c5812cce80dd43 [4/9] x86, sched: Prevent divisions by zero in frequency invariant accounting > > config: i386-randconfig-a011-20200515 (attached as .config) > > compiler: gcc-4.9 (Ubuntu 4.9.3-13ubuntu2) 4.9.3 > > reproduce: > > git checkout df24fd8a5838c3e24dc7a41b37c5812cce80dd43 > > # save the attached .config to linux build tree > > make ARCH=i386 > > > > If you fix the issue, kindly add following tag as appropriate > > Reported-by: kbuild test robot <lkp(a)intel.com&gt; > > > > All errors (new ones prefixed by >>, old ones prefixed by <<): > > > > ld: arch/x86/kernel/smpboot.o: in function `arch_scale_freq_tick': > > > > arch/x86/kernel/smpboot.c:2083: undefined reference to `__udivdi3' > > > > vim +2083 arch/x86/kernel/smpboot.c > > > > 2061 > > 2062 void arch_scale_freq_tick(void) > > 2063 { > > 2064 u64 freq_scale = SCHED_CAPACITY_SCALE; > > 2065 u64 aperf, mperf; > > 2066 u64 acnt, mcnt; > > 2067 > > 2068 if (!arch_scale_freq_invariant()) > > 2069 return; > > 2070 > > 2071 rdmsrl(MSR_IA32_APERF, aperf); > > 2072 rdmsrl(MSR_IA32_MPERF, mperf); > > 2073 > > 2074 acnt = aperf - this_cpu_read(arch_prev_aperf); > > 2075 mcnt = mperf - this_cpu_read(arch_prev_mperf); > > 2076 > > 2077 this_cpu_write(arch_prev_aperf, aperf); > > 2078 this_cpu_write(arch_prev_mperf, mperf); > > 2079 > > 2080 if (check_shl_overflow(acnt, 2*SCHED_CAPACITY_SHIFT, &acnt)) > > 2081 goto error; > > 2082 > > > 2083 if (check_mul_overflow(mcnt, arch_max_freq_ratio, &mcnt) || !mcnt) > > *sigh*,.. I hate computers. I'll try and have a look later, but if if > you have a nice solution Giovanni, don't hessitate to tell me ;-) Hello Peter, today I'm speaking at OSPM but tomorrow I'll see how to fix this.