Re: [PATCH] kernfs: Drop kernfs_rwsem while invoking lookup_positive_unlocked().

[Al Viro]

On Tue, Feb 18, 2025 at 05:39:38PM +0100, Sebastian Andrzej Siewior wrote:

> +	scoped_guard(rcu) {
> +		knparent = find_next_ancestor(kn, NULL);
> +		if (WARN_ON(!knparent)) {
> +			dput(dentry);
> +			return ERR_PTR(-EINVAL);
> +		}

NAK.  dput() is blocking; you *can't* do that under rcu_read_lock().