4.11-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Disseldorp <ddiss@xxxxxxx> commit 6026685de33b0db5b2b6b0e9b41b3a1a3261033c upstream. As with 618763958b22, an open directory may have a NULL private_data pointer prior to readdir. CIFS_ENUMERATE_SNAPSHOTS must check for this before dereference. Fixes: 834170c85978 ("Enable previous version support") Signed-off-by: David Disseldorp <ddiss@xxxxxxx> Signed-off-by: Steve French <smfrench@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/cifs/ioctl.c | 2 ++ 1 file changed, 2 insertions(+) --- a/fs/cifs/ioctl.c +++ b/fs/cifs/ioctl.c @@ -213,6 +213,8 @@ long cifs_ioctl(struct file *filep, unsi rc = smb_mnt_get_fsinfo(xid, tcon, (void __user *)arg); break; case CIFS_ENUMERATE_SNAPSHOTS: + if (pSMBFile == NULL) + break; if (arg == 0) { rc = -EINVAL; goto cifs_ioc_exit;