After the conditional that precedes the following code, inode may be an
ERR_PTR value. This can eg result from a memory allocation failure via the
call to btrfs_iget, and thus does not imply that root is different than
sub_root. Thus, an IS_ERR check is added to ensure that there is no
dereference of inode in this case.
The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)
// <smpl>
@r@
identifier f;
@@
f(...) { ... return ERR_PTR(...); }
@@
identifier r.f, fld;
expression x;
statement S1,S2;
@@
x = f(...)
... when != IS_ERR(x)
(
if (IS_ERR(x) ||...) S1 else S2
|
*x->fld
)
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
---
fs/btrfs/inode.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 160b55b..b322158 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4134,7 +4134,7 @@ struct inode *btrfs_lookup_dentry(struct inode *dir,
struct dentry *dentry)
}
srcu_read_unlock(&root->fs_info->subvol_srcu, index);
- if (root != sub_root) {
+ if (!IS_ERR(inode) && root != sub_root) {
down_read(&root->fs_info->cleanup_work_sem);
if (!(inode->i_sb->s_flags & MS_RDONLY))
btrfs_orphan_cleanup(sub_root);