tree:   https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.4.y
head:   6201d69ba49e810a10a557a4f41fd95c55a61983
commit: 735e7a12a639c6c196ac1acf41f024f84281e491 [1325/3645] lib/ubsan: don't serialize UBSAN report
config: riscv-randconfig-a001-20200310 (attached as .config)
compiler: riscv64-linux-gcc (GCC) 9.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        git checkout 735e7a12a639c6c196ac1acf41f024f84281e491
        # save the attached .config to linux build tree
        GCC_VERSION=9.2.0 make.cross ARCH=riscv 

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

All errors (new ones prefixed by >>):

   riscv64-linux-ld: lib/ubsan.o: in function `test_and_set_bit':
>> arch/riscv/include/asm/bitops.h:74: undefined reference to `__ashlti3'
   riscv64-linux-ld: lib/ubsan.o: in function `get_signed_val':
>> lib/ubsan.c:422: undefined reference to `__ashrti3'

vim +422 lib/ubsan.c

c6d308534aef6c Andrey Ryabinin 2016-01-20  405  
c6d308534aef6c Andrey Ryabinin 2016-01-20  406  void __ubsan_handle_load_invalid_value(struct invalid_value_data *data,
f0996bc2978e02 Andrey Ryabinin 2019-05-06  407  				void *val)
c6d308534aef6c Andrey Ryabinin 2016-01-20  408  {
c6d308534aef6c Andrey Ryabinin 2016-01-20  409  	char val_str[VALUE_LENGTH];
c6d308534aef6c Andrey Ryabinin 2016-01-20  410  
c6d308534aef6c Andrey Ryabinin 2016-01-20  411  	if (suppress_report(&data->location))
c6d308534aef6c Andrey Ryabinin 2016-01-20  412  		return;
c6d308534aef6c Andrey Ryabinin 2016-01-20  413  
735e7a12a639c6 Julien Grall    2019-12-04  414  	ubsan_prologue(&data->location);
c6d308534aef6c Andrey Ryabinin 2016-01-20  415  
c6d308534aef6c Andrey Ryabinin 2016-01-20  416  	val_to_string(val_str, sizeof(val_str), data->type, val);
c6d308534aef6c Andrey Ryabinin 2016-01-20  417  
c6d308534aef6c Andrey Ryabinin 2016-01-20  418  	pr_err("load of value %s is not a valid value for type %s\n",
c6d308534aef6c Andrey Ryabinin 2016-01-20  419  		val_str, data->type->type_name);
c6d308534aef6c Andrey Ryabinin 2016-01-20  420  
735e7a12a639c6 Julien Grall    2019-12-04  421  	ubsan_epilogue();
c6d308534aef6c Andrey Ryabinin 2016-01-20 @422  }

:::::: The code at line 422 was first introduced by commit
:::::: c6d308534aef6c99904bf5862066360ae067abc4 UBSAN: run-time undefined behavior sanity checker

:::::: TO: Andrey Ryabinin <aryabinin@virtuozzo.com>
:::::: CC: Linus Torvalds <torvalds@linux-foundation.org>

---
0-DAY CI Kernel Test Service, Intel Corporation
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