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ext4: fix potential NULL dereference in ext4_free_inodes_counts()

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The ext4_get_group_desc() function returns NULL on error, and
ext4_free_inodes_count() function dereferences it without checking.
There is a check on the next line, but it's too late.

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
This commit is contained in:
Dan Carpenter 2012-05-28 14:16:57 -04:00 committed by Theodore Ts'o
parent e93376c20b
commit bb3d132a24
1 changed files with 6 additions and 4 deletions
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4
fs/ext4/ialloc.c
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@ -508,12 +508,14 @@ static int find_group_orlov(struct super_block *sb, struct inode *parent,
for (i = 0; i < ngroups; i++) {
grp = (parent_group + i) % ngroups;
desc = ext4_get_group_desc(sb, grp, NULL);
if (desc) {
grp_free = ext4_free_inodes_count(sb, desc);
if (desc && grp_free && grp_free >= avefreei) {
if (grp_free && grp_free >= avefreei) {
*group = grp;
return 0;
}
}
}
if (avefreei) {
/*