Re: [PATCH v2] IB/ipoib: fix for rare multicast join race condition.

[Leon Romanovsky <leon-2ukJVAZIZ/Y@public.gmane.org>]

On Mon, Feb 08, 2016 at 04:43:29PM +0000, Estrin, Alex wrote:
> Hi Erez,
>  
> > Can you please elaborate what will avoid the other task that
> > invalidate the priv->broadcast (ipoib_mcast_dev_flush) to do it right
> > after that check?
> 
> I was considering check for IPOIB_FLAG_OPER_UP in mcast task loop 
> would be sufficient as its state is serialized  by priv->lock:
> > >         list_for_each_entry(mcast, &priv->multicast_list, list) {
> > > +               if (!test_bit(IPOIB_FLAG_OPER_UP, &priv->flags)) {
> 
> And I can see your point now. We unlock before calling mcast_join().
> Apparently check for OPER_UP flag should be added along priv->broadcast check
> as it will ensure indication if mcast worker is competing with event handler worker.

Will you plan to respin it?

> 
> Thanks,
> Alex.
> 
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