Re: [BUG] act_ife: sleeping functions called in atomic context

On Thu, Jun 16, 2016 at 1:50 PM, Alexey Khoroshilov
[off-list ref] wrote:

tcf_ife_init() contains a big chunk of code executed with
ife->tcf_lock spinlock held. But that code contains several calls
to sleeping functions:
  populate_metalist() and use_all_metadata()
    -> add_metainfo()
      -> find_ife_oplist(metaid)
        -> read_lock()
        -> try_module_get(o->owner)
      -> kzalloc(sizeof(*mi), GFP_KERNEL);

Hmm, we don't need to hold that spinlock when we create a new ife action,
since we haven't inserted it yet. We do need it when we modify an existing
one. So I am thinking if we can refactor that code to avoid spinlock
whenever possible.

      -> ops->alloc(mi, metaval);
      -> module_put(ops->owner);
  _tcf_ife_cleanup()
    -> module_put()

The same problem is actual for tcf_ife_cleanup() as well.

Huh? Both module_put() and kfree() should not sleep, right?