ext4: fix potential NULL dereference in ext4_free_inodes_counts()
commit bb3d132a24cd8bf5e7773b2d9f9baa58b07a7dae upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 409c2ee..8900f8b 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -488,10 +488,12 @@
for (i = 0; i < ngroups; i++) {
grp = (parent_group + i) % ngroups;
desc = ext4_get_group_desc(sb, grp, NULL);
- grp_free = ext4_free_inodes_count(sb, desc);
- if (desc && grp_free && grp_free >= avefreei) {
- *group = grp;
- return 0;
+ if (desc) {
+ grp_free = ext4_free_inodes_count(sb, desc);
+ if (grp_free && grp_free >= avefreei) {
+ *group = grp;
+ return 0;
+ }
}
}