on 2/22/2023 11:13 PM, Dan Carpenter wrote: > Hi Kemeng, > > https://git-scm.com/docs/git-format-patch#_base_tree_information] > > url: https://github.com/intel-lab-lkp/linux/commits/Kemeng-Shi/ext4-properly-handle-error-of-ext4_init_block_bitmap-in-ext4_read_block_bitmap_nowait/20230221-115830 > base: https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git dev > patch link: https://lore.kernel.org/r/20230221115919.1918161-8-shikemeng%40huaweicloud.com > patch subject: [PATCH 7/7] ext4: improve inode table blocks counting in ext4_num_overhead_clusters > config: riscv-randconfig-m031-20230219 (https://download.01.org/0day-ci/archive/20230222/202302222219.u328sqfs-lkp@xxxxxxxxx/config) > compiler: riscv32-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 <error27@xxxxxxxxx> > | Link: https://lore.kernel.org/r/202302222219.u328sqfs-lkp@xxxxxxxxx/ > > New smatch warnings: > fs/ext4/balloc.c:153 ext4_num_overhead_clusters() error: uninitialized symbol 'block_cluster'. > > vim +/block_cluster +153 fs/ext4/balloc.c [...] > d5b8f31007a937 Theodore Ts'o 2011-09-09 128 /* > 2b59a2fd93873a Kemeng Shi 2023-02-21 129 * For the allocation bitmaps, we first need to check to see > 2b59a2fd93873a Kemeng Shi 2023-02-21 130 * if the block is in the block group. If it is, then check > 2b59a2fd93873a Kemeng Shi 2023-02-21 131 * to see if the cluster is already accounted for in the clusters > 2b59a2fd93873a Kemeng Shi 2023-02-21 132 * used for the base metadata cluster and inode tables cluster. > d5b8f31007a937 Theodore Ts'o 2011-09-09 133 * Normally all of these blocks are contiguous, so the special > d5b8f31007a937 Theodore Ts'o 2011-09-09 134 * case handling shouldn't be necessary except for *very* > d5b8f31007a937 Theodore Ts'o 2011-09-09 135 * unusual file system layouts. > d5b8f31007a937 Theodore Ts'o 2011-09-09 136 */ > d5b8f31007a937 Theodore Ts'o 2011-09-09 137 if (ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp), block_group)) { > b0dd6b70f0fda1 Theodore Ts'o 2012-06-07 138 block_cluster = EXT4_B2C(sbi, > b0dd6b70f0fda1 Theodore Ts'o 2012-06-07 139 ext4_block_bitmap(sb, gdp) - start); > 2b59a2fd93873a Kemeng Shi 2023-02-21 140 if (block_cluster >= base_clusters && > 2b59a2fd93873a Kemeng Shi 2023-02-21 141 (block_cluster < itbl_cluster_start || > 2b59a2fd93873a Kemeng Shi 2023-02-21 142 block_cluster > itbl_cluster_end)) > d5b8f31007a937 Theodore Ts'o 2011-09-09 143 num_clusters++; > d5b8f31007a937 Theodore Ts'o 2011-09-09 144 } > d5b8f31007a937 Theodore Ts'o 2011-09-09 145 > d5b8f31007a937 Theodore Ts'o 2011-09-09 146 if (ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp), block_group)) { > > These two conditions are exactly the same so I don't see why they can't > be combined into one condition. I have read the comment, but I guess I > don't understand ext4 well enough to really understand it. These two conditions check two kinds of bitmap block: *block* bitmap block and *inode* bitmap block. For case that block bitmap in the block group while inode bitmap in a different group, there is a risk to access uninitialized block_cluster. I will fix this in next version, Thanks! -- Best wishes Kemeng Shi
