ksmbd: check return value of xa_store() in krb5_authenticate

xa_store() may fail so check its return value and return error code if
error occurred.

Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: namjaejeon

fs/smb/server/smb2pdu.c

@@ -1594,7 +1594,7 @@ static int krb5_authenticate(struct ksmbd_work *work,
 	struct ksmbd_conn *conn = work->conn;
 	struct ksmbd_session *sess = work->sess;
 	char *in_blob, *out_blob;
-	struct channel *chann = NULL;
+	struct channel *chann = NULL, *old;
 	u64 prev_sess_id;
 	int in_len, out_len;
 	int retval;
@@ -1660,7 +1660,12 @@ static int krb5_authenticate(struct ksmbd_work *work,
 				return -ENOMEM;
 
 			chann->conn = conn;
-			xa_store(&sess->ksmbd_chann_list, (long)conn, chann, KSMBD_DEFAULT_GFP);
+			old = xa_store(&sess->ksmbd_chann_list, (long)conn,
+					chann, KSMBD_DEFAULT_GFP);
+			if (xa_is_err(old)) {
+				kfree(chann);
+				return xa_err(old);
+			}
 		}
 	}