Infiniband: Fix potential NULL d_inode dereference

Code that does this:

	if (!(d_unhashed(tmp) && tmp->d_inode)) {
		...
		simple_unlink(parent->d_inode, tmp);
	}

is broken because:

	!(d_unhashed(tmp) && tmp->d_inode)

is equivalent to:

	!d_unhashed(tmp) || !tmp->d_inode

so it is possible to get into simple_unlink() with tmp->d_inode == NULL.

simple_unlink(), however, assumes tmp->d_inode cannot be NULL.

I think that what was meant is this:

	!d_unhashed(tmp) && tmp->d_inode

and that the logical-not operator or the final close-bracket was misplaced.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Bryan O'Sullivan <bos@pathscale.com>
cc: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/drivers/infiniband/hw/ipath/ipath_fs.c b/drivers/infiniband/hw/ipath/ipath_fs.c
index 4977082..33c45df 100644 (file)
--- a/drivers/infiniband/hw/ipath/ipath_fs.c
+++ b/drivers/infiniband/hw/ipath/ipath_fs.c
@@ -277,7 +277,7 @@ static int remove_file(struct dentry *parent, char *name)
        }
 
        spin_lock(&tmp->d_lock);
-       if (!(d_unhashed(tmp) && tmp->d_inode)) {
+       if (!d_unhashed(tmp) && tmp->d_inode) {
                dget_dlock(tmp);
                __d_drop(tmp);
                spin_unlock(&tmp->d_lock);

diff --git a/drivers/infiniband/hw/qib/qib_fs.c b/drivers/infiniband/hw/qib/qib_fs.c
index 8185458..d242764 100644 (file)
--- a/drivers/infiniband/hw/qib/qib_fs.c
+++ b/drivers/infiniband/hw/qib/qib_fs.c
@@ -455,7 +455,7 @@ static int remove_file(struct dentry *parent, char *name)
        }
 
        spin_lock(&tmp->d_lock);
-       if (!(d_unhashed(tmp) && tmp->d_inode)) {
+       if (!d_unhashed(tmp) && tmp->d_inode) {
                __d_drop(tmp);
                spin_unlock(&tmp->d_lock);
                simple_unlink(parent->d_inode, tmp);