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

On 16-06-16 05:43 PM, Cong Wang wrote:

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

quoted

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.

Does attached (compile tested) patch help?

quoted

       -> 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?

I dont think there is any sleeping there ;->

cheers,
jamal