sparse is warning about an incorrect RCU dereference.
fs/nfs/dir.c:2965:56: warning: incorrect type in argument 1 (different address spaces)
fs/nfs/dir.c:2965:56:    expected struct cred const *
fs/nfs/dir.c:2965:56:    got struct cred const [noderef] __rcu *const cred
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
                                 const struct cred *cred)
 {
        const struct task_struct *parent;
+       const struct cred *pcred;
        u64 ret;
 
        rcu_read_lock();
        for (;;) {
                parent = rcu_dereference(task->real_parent);
-               if (parent == task || cred_fscmp(parent->cred, cred) != 0)
+               pcred = rcu_dereference(parent->cred);
+               if (parent == task || cred_fscmp(pcred, cred) != 0)
                        break;
                task = parent;
        }