Hi Mingzhe, kernel test robot noticed the following build warnings: https://git-scm.com/docs/git-format-patch#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Mingzhe-Zou/bcache-Separate-bch_moving_gc-from-bch_btree_gc/20230629-194834 base: linus/master patch link: https://lore.kernel.org/r/20230629114740.311-1-mingzhe.zou%40easystack.cn patch subject: [PATCH v3] bcache: Separate bch_moving_gc() from bch_btree_gc() config: x86_64-randconfig-m001-20230710 (https://download.01.org/0day-ci/archive/20230716/202307160359.0vHG3r40-lkp@xxxxxxxxx/config) compiler: gcc-12 (Debian 12.2.0-14) 12.2.0 reproduce: (https://download.01.org/0day-ci/archive/20230716/202307160359.0vHG3r40-lkp@xxxxxxxxx/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@xxxxxxxxx> | Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> | Closes: https://lore.kernel.org/r/202307160359.0vHG3r40-lkp@xxxxxxxxx/ New smatch warnings: drivers/md/bcache/btree.c:1887 moving_gc_should_run() error: uninitialized symbol 'used_sectors'. Old smatch warnings: drivers/md/bcache/btree.c:1535 btree_gc_rewrite_node() error: 'n' dereferencing possible ERR_PTR() drivers/md/bcache/btree.c:1551 btree_gc_rewrite_node() error: 'n' dereferencing possible ERR_PTR() vim +/used_sectors +1887 drivers/md/bcache/btree.c 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1856 static bool moving_gc_should_run(struct cache_set *c) 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1857 { 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1858 struct bucket *b; 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1859 struct cache *ca = c->cache; 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1860 size_t moving_gc_threshold = ca->sb.bucket_size >> 2, frag_percent; 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1861 unsigned long used_buckets = 0, frag_buckets = 0, move_buckets = 0; 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1862 unsigned long dirty_sectors = 0, frag_sectors, used_sectors; 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1863 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1864 if (c->gc_stats.in_use > bch_cutoff_writeback_sync) 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1865 return true; 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1866 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1867 mutex_lock(&c->bucket_lock); 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1868 for_each_bucket(b, ca) { 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1869 if (GC_MARK(b) != GC_MARK_DIRTY) 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1870 continue; Smatch is complaining that we might not enter the loop or there could be no GC_MARK_DIRTY entries. 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1871 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1872 used_buckets++; 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1873 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1874 used_sectors = GC_SECTORS_USED(b); 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1875 dirty_sectors += used_sectors; 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1876 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1877 if (used_sectors < ca->sb.bucket_size) 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1878 frag_buckets++; 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1879 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1880 if (used_sectors <= moving_gc_threshold) 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1881 move_buckets++; 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1882 } 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1883 mutex_unlock(&c->bucket_lock); 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1884 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1885 c->fragment_nbuckets = frag_buckets; 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1886 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 @1887 if (used_sectors < c->nbuckets * bch_cutoff_writeback / 100) It's sort of weird that we are using the used_sectors value from the last MARK_DIRTY iteration through the loop. Should it be used_buckets? 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1888 return false; 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1889 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1890 if (move_buckets > ca->heap.size) 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1891 return true; 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1892 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1893 frag_sectors = used_buckets * ca->sb.bucket_size - dirty_sectors; 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1894 frag_percent = div_u64(frag_sectors * 100, ca->sb.bucket_size * c->nbuckets); 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1895 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1896 if (frag_percent >= COPY_GC_PERCENT) 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1897 return true; 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1898 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1899 if (used_sectors > c->nbuckets * bch_cutoff_writeback_sync / 100) 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1900 return true; 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1901 4b0cf76f1e36e7 Mingzhe Zou 2023-06-29 1902 return false; cafe563591446c Kent Overstreet 2013-03-23 1903 } -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
