8 p.m.
Hi Harshad,
url:
https://github.com/0day-ci/linux/commits/Harshad-Shirwadkar/ext4-drop-s_m...
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(a)intel.com>
Reported-by: Dan Carpenter <dan.carpenter(a)oracle.com>
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
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Dan Carpenter