lkml.org 
[lkml]   [2014]   [Jan]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH net] net: hyperv: initialize link status correctly
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@redhat.com>
>>> 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@microsoft.com>
>>>> Cc: K. Y. Srinivasan <kys@microsoft.com>
>>>> Reported-by: Di Nie <dnie@redhat.com>
>>>> Tested-by: Di Nie <dnie@redhat.com>
>>>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>>> 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.


\
 
 \ /
  Last update: 2014-01-27 12:01    [W:0.048 / U:0.032 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site