tree: https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git fix-bz-206443 head: c20bac9bf82cd6560d269aa1e885e036d9e418b3 commit: cd19e90e29ccc914b52eeb53afef676edaac911c [3/6] ext4: fix potential race between online resizing and write operations reproduce: # apt-get install sparse # sparse version: v0.6.1-173-ge0787745-dirty git checkout cd19e90e29ccc914b52eeb53afef676edaac911c make ARCH=x86_64 allmodconfig make C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' If you fix the issue, kindly add following tag Reported-by: kbuild test robot <lkp@xxxxxxxxx> sparse warnings: (new ones prefixed by >>) >> fs/ext4/balloc.c:285:16: sparse: sparse: incompatible types in comparison expression (different address spaces): >> fs/ext4/balloc.c:285:16: sparse: struct buffer_head *[noderef] <asn:4> * >> fs/ext4/balloc.c:285:16: sparse: struct buffer_head ** -- >> fs/ext4/resize.c:894:9: sparse: sparse: incompatible types in comparison expression (different address spaces): >> fs/ext4/resize.c:894:9: sparse: struct buffer_head *[noderef] <asn:4> * >> fs/ext4/resize.c:894:9: sparse: struct buffer_head ** fs/ext4/resize.c:952:9: sparse: sparse: incompatible types in comparison expression (different address spaces): fs/ext4/resize.c:952:9: sparse: struct buffer_head *[noderef] <asn:4> * fs/ext4/resize.c:952:9: sparse: struct buffer_head ** vim +285 fs/ext4/balloc.c 245 246 /* 247 * The free blocks are managed by bitmaps. A file system contains several 248 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap 249 * block for inodes, N blocks for the inode table and data blocks. 250 * 251 * The file system contains group descriptors which are located after the 252 * super block. Each descriptor contains the number of the bitmap block and 253 * the free blocks count in the block. The descriptors are loaded in memory 254 * when a file system is mounted (see ext4_fill_super). 255 */ 256 257 /** 258 * ext4_get_group_desc() -- load group descriptor from disk 259 * @sb: super block 260 * @block_group: given block group 261 * @bh: pointer to the buffer head to store the block 262 * group descriptor 263 */ 264 struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb, 265 ext4_group_t block_group, 266 struct buffer_head **bh) 267 { 268 unsigned int group_desc; 269 unsigned int offset; 270 ext4_group_t ngroups = ext4_get_groups_count(sb); 271 struct ext4_group_desc *desc; 272 struct ext4_sb_info *sbi = EXT4_SB(sb); 273 struct buffer_head *bh_p; 274 275 if (block_group >= ngroups) { 276 ext4_error(sb, "block_group >= groups_count - block_group = %u," 277 " groups_count = %u", block_group, ngroups); 278 279 return NULL; 280 } 281 282 group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb); 283 offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1); 284 rcu_read_lock(); > 285 bh_p = rcu_dereference(sbi->s_group_desc)[group_desc]; 286 /* 287 * We can unlock here since the pointer being dereferenced won't be 288 * dereferenced again. By looking at the usage in add_new_gdb() the 289 * value isn't modified, just the pointer, and so it remains valid. 290 */ 291 rcu_read_unlock(); 292 if (!bh_p) { 293 ext4_error(sb, "Group descriptor not loaded - " 294 "block_group = %u, group_desc = %u, desc = %u", 295 block_group, group_desc, offset); 296 return NULL; 297 } 298 299 desc = (struct ext4_group_desc *)( 300 (__u8 *)bh_p->b_data + 301 offset * EXT4_DESC_SIZE(sb)); 302 if (bh) 303 *bh = bh_p; 304 return desc; 305 } 306 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx
