Commit c0d0e351 authored by OGAWA Hirofumi's avatar OGAWA Hirofumi Committed by Linus Torvalds

fat: fix using uninitialized fields of fat_inode/fsinfo_inode

Recently fallocate patch was merged and it uses
MSDOS_I(inode)->mmu_private at fat_evict_inode().  However,
fat_inode/fsinfo_inode that was introduced in past didn't initialize
MSDOS_I(inode) properly.

With those combinations, it became the cause of accessing random entry
in FAT area.

Link: 's avatarOGAWA Hirofumi <>
Reported-by: 's avatarMoreno Bartalucci <>
Tested-by: 's avatarMoreno Bartalucci <>
Cc: <>
Signed-off-by: 's avatarAndrew Morton <>
Signed-off-by: 's avatarLinus Torvalds <>
parent ca5b58ea
......@@ -1359,6 +1359,16 @@ static int parse_options(struct super_block *sb, char *options, int is_vfat,
return 0;
static void fat_dummy_inode_init(struct inode *inode)
/* Initialize this dummy inode to work as no-op. */
MSDOS_I(inode)->mmu_private = 0;
MSDOS_I(inode)->i_start = 0;
MSDOS_I(inode)->i_logstart = 0;
MSDOS_I(inode)->i_attrs = 0;
MSDOS_I(inode)->i_pos = 0;
static int fat_read_root(struct inode *inode)
struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
......@@ -1803,12 +1813,13 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
fat_inode = new_inode(sb);
if (!fat_inode)
goto out_fail;
MSDOS_I(fat_inode)->i_pos = 0;
sbi->fat_inode = fat_inode;
fsinfo_inode = new_inode(sb);
if (!fsinfo_inode)
goto out_fail;
fsinfo_inode->i_ino = MSDOS_FSINFO_INO;
sbi->fsinfo_inode = fsinfo_inode;
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