[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <PH7PR21MB31169E29DF8600F857CC141ACAB3A@PH7PR21MB3116.namprd21.prod.outlook.com>
Date: Mon, 13 Nov 2023 15:55:08 +0000
From: Haiyang Zhang <haiyangz@...rosoft.com>
To: Simon Horman <horms@...nel.org>
CC: "linux-hyperv@...r.kernel.org" <linux-hyperv@...r.kernel.org>,
"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
KY Srinivasan <kys@...rosoft.com>,
"wei.liu@...nel.org" <wei.liu@...nel.org>,
Dexuan Cui <decui@...rosoft.com>,
"edumazet@...gle.com" <edumazet@...gle.com>,
"kuba@...nel.org" <kuba@...nel.org>,
"pabeni@...hat.com" <pabeni@...hat.com>,
"davem@...emloft.net" <davem@...emloft.net>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"stable@...r.kernel.org" <stable@...r.kernel.org>
Subject: RE: [PATCH net,v4, 2/3] hv_netvsc: Fix race of
register_netdevice_notifier and VF register
> -----Original Message-----
> From: Simon Horman <horms@...nel.org>
> Sent: Sunday, November 12, 2023 4:41 AM
> To: Haiyang Zhang <haiyangz@...rosoft.com>
> Cc: linux-hyperv@...r.kernel.org; netdev@...r.kernel.org; KY Srinivasan
> <kys@...rosoft.com>; wei.liu@...nel.org; Dexuan Cui
> <decui@...rosoft.com>; edumazet@...gle.com; kuba@...nel.org;
> pabeni@...hat.com; davem@...emloft.net; linux-kernel@...r.kernel.org;
> stable@...r.kernel.org
> Subject: Re: [PATCH net,v4, 2/3] hv_netvsc: Fix race of
> register_netdevice_notifier and VF register
>
> On Fri, Nov 10, 2023 at 06:38:59AM -0800, Haiyang Zhang wrote:
> > If VF NIC is registered earlier, NETDEV_REGISTER event is replayed,
> > but NETDEV_POST_INIT is not.
> >
> > Move register_netdevice_notifier() earlier, so the call back
> > function is set before probing.
> >
> > Cc: stable@...r.kernel.org
> > Fixes: e04e7a7bbd4b ("hv_netvsc: Fix a deadlock by getting rtnl lock earlier
> in netvsc_probe()")
> > Reported-by: Dexuan Cui <decui@...rosoft.com>
> > Signed-off-by: Haiyang Zhang <haiyangz@...rosoft.com>
> > Reviewed-by: Wojciech Drewek <wojciech.drewek@...el.com>
> >
> > ---
> > v3:
> > Divide it into two patches, suggested by Jakub Kicinski.
> > v2:
> > Fix rtnl_unlock() in error handling as found by Wojciech Drewek.
> > ---
> > drivers/net/hyperv/netvsc_drv.c | 7 +++++--
> > 1 file changed, 5 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/hyperv/netvsc_drv.c
> b/drivers/net/hyperv/netvsc_drv.c
> > index 5e528a76f5f5..1d1491da303b 100644
> > --- a/drivers/net/hyperv/netvsc_drv.c
> > +++ b/drivers/net/hyperv/netvsc_drv.c
> > @@ -2793,11 +2793,14 @@ static int __init netvsc_drv_init(void)
> > }
> > netvsc_ring_bytes = ring_size * PAGE_SIZE;
> >
> > + register_netdevice_notifier(&netvsc_netdev_notifier);
> > +
> > ret = vmbus_driver_register(&netvsc_drv);
> > - if (ret)
> > + if (ret) {
> > + unregister_netdevice_notifier(&netvsc_netdev_notifier);
> > return ret;
> > + }
> >
> > - register_netdevice_notifier(&netvsc_netdev_notifier);
> > return 0;
> > }
>
> Hi Haiyang Zhang,
>
> functionally this change looks good to me, thanks!
>
> I'm wondering if we could improve things slightly by using a more idiomatic
> form for the error path. Something like the following (completely untested!).
>
> My reasoning is that this way things are less likely go to wrong if more
> error conditions are added to this function later.
>
> ...
>
> register_netdevice_notifier(&netvsc_netdev_notifier);
>
> ret = vmbus_driver_register(&netvsc_drv);
> if (ret)
> goto err_unregister_netdevice_notifier;
>
> return 0;
>
> err_unregister_netdevice_notifier:
> unregister_netdevice_notifier(&netvsc_netdev_notifier);
> return ret;
> }
Thanks for the suggested idiomatic form. I will update it.
- Haiyang
Powered by blists - more mailing lists