arch/arm64/kernel/topology.c:367:22: sparse: sparse: dereference of noderef expression

From: kernel test robot
Date: Wed Jan 06 2021 - 00:51:50 EST


tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: e71ba9452f0b5b2e8dc8aa5445198cd9214a6a62
commit: 68c5debcc06d6d24f15dbf978780fc5efc147d5e arm64: implement CPPC FFH support using AMUs
date: 8 weeks ago
config: arm64-randconfig-s032-20210106 (attached as .config)
compiler: aarch64-linux-gcc (GCC) 9.3.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# apt-get install sparse
# sparse version: v0.6.3-208-g46a52ca4-dirty
# https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=68c5debcc06d6d24f15dbf978780fc5efc147d5e
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout 68c5debcc06d6d24f15dbf978780fc5efc147d5e
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=arm64

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


"sparse warnings: (new ones prefixed by >>)"
>> arch/arm64/kernel/topology.c:367:22: sparse: sparse: dereference of noderef expression

vim +367 arch/arm64/kernel/topology.c

362
363 int cpc_read_ffh(int cpu, struct cpc_reg *reg, u64 *val)
364 {
365 int ret = -EOPNOTSUPP;
366
> 367 switch ((u64)reg->address) {
368 case 0x0:
369 ret = counters_read_on_cpu(cpu, cpu_read_corecnt, val);
370 break;
371 case 0x1:
372 ret = counters_read_on_cpu(cpu, cpu_read_constcnt, val);
373 break;
374 }
375
376 if (!ret) {
377 *val &= GENMASK_ULL(reg->bit_offset + reg->bit_width - 1,
378 reg->bit_offset);
379 *val >>= reg->bit_offset;
380 }
381
382 return ret;
383 }
384

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx

Attachment: .config.gz
Description: application/gzip