[PATCH v4] proc: Allow pid_revalidate() during LOOKUP_RCU

[Al Viro]

On Tue, Jan 05, 2021 at 04:50:05PM +0000, Al Viro wrote:

> struct dentry *d_find_alias_rcu(struct inode *inode)
> {
> 	struct hlist_head *l = &inode->i_dentry;
>         struct dentry *de = NULL;
> 
> 	spin_lock(&inode->i_lock);
> 	// ->i_dentry and ->i_rcu are colocated, but the latter won't be
> 	// used without having I_FREEING set, which means no aliases left
> 	if (inode->i_state & I_FREEING) {
> 		spin_unlock(&inode->i_lock);
> 		return NULL;
> 	}
> 	// we can safely access inode->i_dentry
>         if (hlist_empty(p)) {

	if (hlist_empty(l)) {

obviously...