[PATCH 4.19 188/211] ovl: Fix dereferencing possible ERR_PTR()

[Greg Kroah-Hartman]

From: Ding Xiang <dingxiang@xxxxxxxxxxxxxxxxxxxx>

commit 97f024b9171e74c4443bbe8a8dce31b917f97ac5 upstream.

if ovl_encode_real_fh() fails, no memory was allocated
and the error in the error-valued pointer should be returned.

Fixes: 9b6faee07470 ("ovl: check ERR_PTR() return value from ovl_encode_fh()")
Signed-off-by: Ding Xiang <dingxiang@xxxxxxxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # v4.16+
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/overlayfs/export.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/fs/overlayfs/export.c
+++ b/fs/overlayfs/export.c
@@ -230,9 +230,8 @@ static int ovl_d_to_fh(struct dentry *de
 	/* Encode an upper or lower file handle */
 	fh = ovl_encode_real_fh(enc_lower ? ovl_dentry_lower(dentry) :
 				ovl_dentry_upper(dentry), !enc_lower);
-	err = PTR_ERR(fh);
 	if (IS_ERR(fh))
-		goto fail;
+		return PTR_ERR(fh);
 
 	err = -EOVERFLOW;
 	if (fh->len > buflen)