nfsd: Fix a memory leak in an error handling path

If this memdup_user() call fails, the memory allocated in a previous call
a few lines above should be freed. Otherwise it leaks.

Fixes: 6ee95d1c ("nfsd: add support for upcall version 2")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/nfsd/nfs4recover.c

@@ -815,8 +815,10 @@ __cld_pipe_inprogress_downcall(const struct cld_msg_v2 __user *cmsg,
 				princhash.data = memdup_user(
 						&ci->cc_princhash.cp_data,
 						princhashlen);
-				if (IS_ERR_OR_NULL(princhash.data))
+				if (IS_ERR_OR_NULL(princhash.data)) {
+					kfree(name.data);
 					return -EFAULT;
+				}
 				princhash.len = princhashlen;
 			} else
 				princhash.len = 0;