Hi Harshad, url: https://github.com/0day-ci/linux/commits/Harshad-Shirwadkar/ext4-drop-s_mb_bal_lock-and-convert-protected-fields-to-atomic/20210210-054647 base: https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git dev config: s390-randconfig-m031-20210209 (attached as .config) compiler: s390-linux-gcc (GCC) 9.3.0 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp@xxxxxxxxx> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> New smatch warnings: fs/ext4/mballoc.c:930 ext4_mb_choose_next_group_cr1() error: uninitialized symbol 'avg_fragment_size'. vim +/avg_fragment_size +930 fs/ext4/mballoc.c ef4eebad9c018a Harshad Shirwadkar 2021-02-09 878 static int ext4_mb_choose_next_group_cr1(struct ext4_allocation_context *ac, ef4eebad9c018a Harshad Shirwadkar 2021-02-09 879 int *new_cr, ext4_group_t *group, ext4_group_t ngroups) ef4eebad9c018a Harshad Shirwadkar 2021-02-09 880 { ef4eebad9c018a Harshad Shirwadkar 2021-02-09 881 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); ef4eebad9c018a Harshad Shirwadkar 2021-02-09 882 int avg_fragment_size, best_so_far; ef4eebad9c018a Harshad Shirwadkar 2021-02-09 883 struct rb_node *node, *found; ef4eebad9c018a Harshad Shirwadkar 2021-02-09 884 struct ext4_group_info *grp; ef4eebad9c018a Harshad Shirwadkar 2021-02-09 885 ef4eebad9c018a Harshad Shirwadkar 2021-02-09 886 /* ef4eebad9c018a Harshad Shirwadkar 2021-02-09 887 * If there is contention on the lock, instead of waiting for the lock ef4eebad9c018a Harshad Shirwadkar 2021-02-09 888 * to become available, just continue searching lineraly. We'll resume ef4eebad9c018a Harshad Shirwadkar 2021-02-09 889 * our rb tree search later starting at ac->ac_last_optimal_group. ef4eebad9c018a Harshad Shirwadkar 2021-02-09 890 */ ef4eebad9c018a Harshad Shirwadkar 2021-02-09 891 if (!read_trylock(&sbi->s_mb_rb_lock)) ef4eebad9c018a Harshad Shirwadkar 2021-02-09 892 return 1; ef4eebad9c018a Harshad Shirwadkar 2021-02-09 893 ef4eebad9c018a Harshad Shirwadkar 2021-02-09 894 if (ac->ac_flags & EXT4_MB_CR1_OPTIMIZED) { ef4eebad9c018a Harshad Shirwadkar 2021-02-09 895 /* We have found something at CR 1 in the past */ ef4eebad9c018a Harshad Shirwadkar 2021-02-09 896 grp = ext4_get_group_info(ac->ac_sb, ac->ac_last_optimal_group); ef4eebad9c018a Harshad Shirwadkar 2021-02-09 897 for (found = rb_next(&grp->bb_avg_fragment_size_rb); found != NULL; ef4eebad9c018a Harshad Shirwadkar 2021-02-09 898 found = rb_next(found)) { ef4eebad9c018a Harshad Shirwadkar 2021-02-09 899 grp = rb_entry(found, struct ext4_group_info, ef4eebad9c018a Harshad Shirwadkar 2021-02-09 900 bb_avg_fragment_size_rb); ef4eebad9c018a Harshad Shirwadkar 2021-02-09 901 /* ef4eebad9c018a Harshad Shirwadkar 2021-02-09 902 * Perform this check without locking, we'll lock later ef4eebad9c018a Harshad Shirwadkar 2021-02-09 903 * to confirm. ef4eebad9c018a Harshad Shirwadkar 2021-02-09 904 */ ef4eebad9c018a Harshad Shirwadkar 2021-02-09 905 if (likely(ext4_mb_good_group(ac, grp->bb_group, 1))) ef4eebad9c018a Harshad Shirwadkar 2021-02-09 906 break; ef4eebad9c018a Harshad Shirwadkar 2021-02-09 907 } ef4eebad9c018a Harshad Shirwadkar 2021-02-09 908 ef4eebad9c018a Harshad Shirwadkar 2021-02-09 909 goto done; ef4eebad9c018a Harshad Shirwadkar 2021-02-09 910 } ef4eebad9c018a Harshad Shirwadkar 2021-02-09 911 ef4eebad9c018a Harshad Shirwadkar 2021-02-09 912 node = sbi->s_mb_avg_fragment_size_root.rb_node; ef4eebad9c018a Harshad Shirwadkar 2021-02-09 913 best_so_far = 0; ef4eebad9c018a Harshad Shirwadkar 2021-02-09 914 found = NULL; ef4eebad9c018a Harshad Shirwadkar 2021-02-09 915 ef4eebad9c018a Harshad Shirwadkar 2021-02-09 916 while (node) { ef4eebad9c018a Harshad Shirwadkar 2021-02-09 917 grp = rb_entry(node, struct ext4_group_info, ef4eebad9c018a Harshad Shirwadkar 2021-02-09 918 bb_avg_fragment_size_rb); ef4eebad9c018a Harshad Shirwadkar 2021-02-09 919 /* ef4eebad9c018a Harshad Shirwadkar 2021-02-09 920 * Perform this check without locking, we'll lock later to confirm. ef4eebad9c018a Harshad Shirwadkar 2021-02-09 921 */ ef4eebad9c018a Harshad Shirwadkar 2021-02-09 922 if (ext4_mb_good_group(ac, grp->bb_group, 1)) { ef4eebad9c018a Harshad Shirwadkar 2021-02-09 923 avg_fragment_size = grp->bb_fragments ? ef4eebad9c018a Harshad Shirwadkar 2021-02-09 924 grp->bb_free / grp->bb_fragments : 0; ef4eebad9c018a Harshad Shirwadkar 2021-02-09 925 if (!best_so_far || avg_fragment_size < best_so_far) { ef4eebad9c018a Harshad Shirwadkar 2021-02-09 926 best_so_far = avg_fragment_size; ef4eebad9c018a Harshad Shirwadkar 2021-02-09 927 found = node; ef4eebad9c018a Harshad Shirwadkar 2021-02-09 928 } ef4eebad9c018a Harshad Shirwadkar 2021-02-09 929 } avg_fragment_size not initialized on else path. ef4eebad9c018a Harshad Shirwadkar 2021-02-09 @930 if (avg_fragment_size > ac->ac_g_ex.fe_len) ef4eebad9c018a Harshad Shirwadkar 2021-02-09 931 node = node->rb_right; ef4eebad9c018a Harshad Shirwadkar 2021-02-09 932 else ef4eebad9c018a Harshad Shirwadkar 2021-02-09 933 node = node->rb_left; ef4eebad9c018a Harshad Shirwadkar 2021-02-09 934 } ef4eebad9c018a Harshad Shirwadkar 2021-02-09 935 ef4eebad9c018a Harshad Shirwadkar 2021-02-09 936 done: ef4eebad9c018a Harshad Shirwadkar 2021-02-09 937 if (found) { ef4eebad9c018a Harshad Shirwadkar 2021-02-09 938 grp = rb_entry(found, struct ext4_group_info, ef4eebad9c018a Harshad Shirwadkar 2021-02-09 939 bb_avg_fragment_size_rb); ef4eebad9c018a Harshad Shirwadkar 2021-02-09 940 *group = grp->bb_group; ef4eebad9c018a Harshad Shirwadkar 2021-02-09 941 ac->ac_flags |= EXT4_MB_CR1_OPTIMIZED; ef4eebad9c018a Harshad Shirwadkar 2021-02-09 942 } else { ef4eebad9c018a Harshad Shirwadkar 2021-02-09 943 *new_cr = 2; ef4eebad9c018a Harshad Shirwadkar 2021-02-09 944 } ef4eebad9c018a Harshad Shirwadkar 2021-02-09 945 ef4eebad9c018a Harshad Shirwadkar 2021-02-09 946 read_unlock(&sbi->s_mb_rb_lock); ef4eebad9c018a Harshad Shirwadkar 2021-02-09 947 ac->ac_last_optimal_group = *group; ef4eebad9c018a Harshad Shirwadkar 2021-02-09 948 return 0; ef4eebad9c018a Harshad Shirwadkar 2021-02-09 949 } --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx
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