configfs: Fix potential NULL d_inode dereference
Code that does this:
if (!(d_unhashed(dentry) && dentry->d_inode)) {
...
simple_unlink(parent->d_inode, dentry);
}
is broken because:
!(d_unhashed(dentry) && dentry->d_inode)
is equivalent to:
!d_unhashed(dentry) || !dentry->d_inode
so it is possible to get into simple_unlink() with dentry->d_inode == NULL.
simple_unlink(), however, assumes dentry->d_inode cannot be NULL.
I think that what was meant is this:
!d_unhashed(dentry) && dentry->d_inode
and that the logical-not operator or the final close-bracket was misplaced.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/configfs/inode.c b/fs/configfs/inode.c
index 60727db..5423a6a 100644
--- a/fs/configfs/inode.c
+++ b/fs/configfs/inode.c
@@ -236,7 +236,7 @@
if (dentry) {
spin_lock(&dentry->d_lock);
- if (!(d_unhashed(dentry) && dentry->d_inode)) {
+ if (!d_unhashed(dentry) && dentry->d_inode) {
dget_dlock(dentry);
__d_drop(dentry);
spin_unlock(&dentry->d_lock);