On Mon, 2014-01-27 at 18:28 +0800, Jason Wang wrote: > On 01/27/2014 06:22 PM, Ben Hutchings wrote: > > On Mon, 2014-01-27 at 17:40 +0800, Jason Wang wrote: > >> On 01/27/2014 04:35 PM, David Miller wrote: > >>> From: Jason Wang <jasowang@xxxxxxxxxx> > >>> Date: Mon, 27 Jan 2014 15:30:54 +0800 > >>> > >>>> Call netif_carrier_on() after register_device(). Otherwise it won't work since > >>>> the device was still in NETREG_UNINITIALIZED state. > >>>> > >>>> Fixes a68f9614614749727286f675d15f1e09d13cb54a > >>>> (hyperv: Fix race between probe and open calls) > >>>> > >>>> Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> > >>>> Cc: K. Y. Srinivasan <kys@xxxxxxxxxxxxx> > >>>> Reported-by: Di Nie <dnie@xxxxxxxxxx> > >>>> Tested-by: Di Nie <dnie@xxxxxxxxxx> > >>>> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx> > >>> A device up can occur at the moment you call register_netdevice(), > >>> therefore that up call can see the carrier as down and fail or > >>> similar. So you really cannot resolve the carrier to be on in this > >>> way. > >> True, we need a workqueue to synchronize them. > > Whatever for? All you need to do is: > > > > rtnl_lock(); > > register_netdevice(); > > netif_carrier_on(); > > rtnl_unlock(); > > > > It would be nice if we could make the current code work with a change in > > the core, though. > > > > Ben. > > > > Looks like the link status interrupt may happen during this (after > netvsc_device_add() was called by rndis_filter_device_add()) without any > synchronization. This may lead a wrong link status here. Now I'm confused - if there's a link status interrupt, why are you setting the carrier on initially? Ben. -- Ben Hutchings If at first you don't succeed, you're doing about average.
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