Re: [PATCH bpf-next v10 06/10] bpf,landlock: Add a new map type: inode

From: Al Viro
Date: Sun Sep 08 2019 - 18:20:12 EST


On Mon, Sep 09, 2019 at 12:09:57AM +0200, Mickaël Salaün wrote:

> >>> + rcu_read_lock();
> >>> + ptr = htab_map_lookup_elem(map, &inode);
> >>> + iput(inode);

Wait a sec. You are doing _what_ under rcu_read_lock()?

> >>> + if (IS_ERR(ptr)) {
> >>> + ret = PTR_ERR(ptr);
> >>> + } else if (!ptr) {
> >>> + ret = -ENOENT;
> >>> + } else {
> >>> + ret = 0;
> >>> + copy_map_value(map, value, ptr);
> >>> + }
> >>> + rcu_read_unlock();