On Thu 08-09-22 14:00:17, Dan Carpenter wrote: > Hi Jan, > > https://git-scm.com/docs/git-format-patch#_base_tree_information] > > url: https://github.com/intel-lab-lkp/linux/commits/Jan-Kara/ext4-Fix-performance-regression-with-mballoc/20220907-000945 > base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 53e99dcff61e1523ec1c3628b2d564ba15d32eb7 > config: m68k-randconfig-m041-20220906 (https://download.01.org/0day-ci/archive/20220907/202209071206.u1iHKVzB-lkp@xxxxxxxxx/config) > compiler: m68k-linux-gcc (GCC) 12.1.0 > > If you fix the issue, kindly add following tag where applicable > Reported-by: kernel test robot <lkp@xxxxxxxxx> > Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> > > New smatch warnings: > fs/ext4/mballoc.c:945 ext4_mb_choose_next_group_cr1() error: uninitialized symbol 'grp'. > > vim +/grp +945 fs/ext4/mballoc.c > > 196e402adf2e4c Harshad Shirwadkar 2021-04-01 909 static void ext4_mb_choose_next_group_cr1(struct ext4_allocation_context *ac, > 196e402adf2e4c Harshad Shirwadkar 2021-04-01 910 int *new_cr, ext4_group_t *group, ext4_group_t ngroups) > 196e402adf2e4c Harshad Shirwadkar 2021-04-01 911 { > 196e402adf2e4c Harshad Shirwadkar 2021-04-01 912 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); > 31b571b608cf66 Jan Kara 2022-09-06 913 struct ext4_group_info *grp, *iter; > 31b571b608cf66 Jan Kara 2022-09-06 914 int i; > 196e402adf2e4c Harshad Shirwadkar 2021-04-01 915 > 196e402adf2e4c Harshad Shirwadkar 2021-04-01 916 if (unlikely(ac->ac_flags & EXT4_MB_CR1_OPTIMIZED)) { > 196e402adf2e4c Harshad Shirwadkar 2021-04-01 917 if (sbi->s_mb_stats) > 196e402adf2e4c Harshad Shirwadkar 2021-04-01 918 atomic_inc(&sbi->s_bal_cr1_bad_suggestions); > 31b571b608cf66 Jan Kara 2022-09-06 919 } > 31b571b608cf66 Jan Kara 2022-09-06 920 > 31b571b608cf66 Jan Kara 2022-09-06 921 for (i = mb_avg_fragment_size_order(ac->ac_sb, ac->ac_g_ex.fe_len); > 31b571b608cf66 Jan Kara 2022-09-06 922 i < MB_NUM_ORDERS(ac->ac_sb); i++) { > 31b571b608cf66 Jan Kara 2022-09-06 923 if (list_empty(&sbi->s_mb_avg_fragment_size[i])) > 31b571b608cf66 Jan Kara 2022-09-06 924 continue; > 31b571b608cf66 Jan Kara 2022-09-06 925 read_lock(&sbi->s_mb_avg_fragment_size_locks[i]); > 31b571b608cf66 Jan Kara 2022-09-06 926 if (list_empty(&sbi->s_mb_avg_fragment_size[i])) { > 31b571b608cf66 Jan Kara 2022-09-06 927 read_unlock(&sbi->s_mb_largest_free_orders_locks[i]); > 31b571b608cf66 Jan Kara 2022-09-06 928 continue; > > Smatch worries that we can hit these two continues on every iteration. > Why not just initialize "grp = NULL;" at the start of the function? Yes, good point. It may even be possible in some rare racy cornercase. I'll do what you suggest. Thanks! Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
