From: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
commit 03a8bb0e53d9562276045bdfcf2b5de2e4cff5a1 upstream. Please apply
to 4.4-stable.
As Al pointed, d_revalidate should return RCU lookup before using d_inode.
This was originally introduced by:
commit 34286d666230 ("fs: rcu-walk aware d_revalidate method").
Reported-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
Cc: Theodore Ts'o <tytso@xxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
---
fs/ext4/crypto.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c
index 1259ade2f10a..9d6c2dcf1bd0 100644
--- a/fs/ext4/crypto.c
+++ b/fs/ext4/crypto.c
@@ -34,6 +34,7 @@
#include <linux/random.h>
#include <linux/scatterlist.h>
#include <linux/spinlock_types.h>
+#include <linux/namei.h>
#include "ext4_extents.h"
#include "xattr.h"
@@ -481,6 +482,9 @@ static int ext4_d_revalidate(struct dentry *dentry, unsigned int flags)
struct ext4_crypt_info *ci;
int dir_has_key, cached_with_key;
+ if (flags & LOOKUP_RCU)
+ return -ECHILD;
+
dir = dget_parent(dentry);
if (!ext4_encrypted_inode(d_inode(dir))) {
dput(dir);
--
2.13.0.rc1.294.g07d810a77f-goog