> -----Original Message----- > From: Wojciech Drewek <wojciech.drewek@xxxxxxxxx> > Sent: Thursday, October 26, 2023 6:48 AM > To: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>; linux-hyperv@xxxxxxxxxxxxxxx; > netdev@xxxxxxxxxxxxxxx > Cc: KY Srinivasan <kys@xxxxxxxxxxxxx>; wei.liu@xxxxxxxxxx; Dexuan Cui > <decui@xxxxxxxxxxxxx>; edumazet@xxxxxxxxxx; kuba@xxxxxxxxxx; > pabeni@xxxxxxxxxx; davem@xxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > stable@xxxxxxxxxxxxxxx > Subject: Re: [PATCH net] hv_netvsc: fix race of netvsc and VF > register_netdevice > > [You don't often get email from wojciech.drewek@xxxxxxxxx. Learn why this is > important at https://aka.ms/LearnAboutSenderIdentification ] > > On 25.10.2023 23:16, Haiyang Zhang wrote: > > The rtnl lock also needs to be held before rndis_filter_device_add() > > which advertises nvsp_2_vsc_capability / sriov bit, and triggers > > VF NIC offering and registering. If VF NIC finished register_netdev() > > earlier it may cause name based config failure. > > > > To fix this issue, move the call to rtnl_lock() before > > rndis_filter_device_add(), so VF will be registered later than netvsc > > / synthetic NIC, and gets a name numbered (ethX) after netvsc. > > > > And, move register_netdevice_notifier() earlier, so the call back > > function is set before probing. > > > > Cc: stable@xxxxxxxxxxxxxxx > > Fixes: e04e7a7bbd4b ("hv_netvsc: Fix a deadlock by getting rtnl lock earlier > in netvsc_probe()") > > Signed-off-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> > > > > --- > > drivers/net/hyperv/netvsc_drv.c | 30 +++++++++++++++++++----------- > > 1 file changed, 19 insertions(+), 11 deletions(-) > > > > diff --git a/drivers/net/hyperv/netvsc_drv.c > b/drivers/net/hyperv/netvsc_drv.c > > index 3ba3c8fb28a5..feca1391f756 100644 > > --- a/drivers/net/hyperv/netvsc_drv.c > > +++ b/drivers/net/hyperv/netvsc_drv.c > > @@ -2531,15 +2531,6 @@ static int netvsc_probe(struct hv_device *dev, > > goto devinfo_failed; > > } > > > > - nvdev = rndis_filter_device_add(dev, device_info); > > - if (IS_ERR(nvdev)) { > > - ret = PTR_ERR(nvdev); > > - netdev_err(net, "unable to add netvsc device (ret %d)\n", ret); > > - goto rndis_failed; > > - } > > - > > - eth_hw_addr_set(net, device_info->mac_adr); > > - > > /* We must get rtnl lock before scheduling nvdev->subchan_work, > > * otherwise netvsc_subchan_work() can get rtnl lock first and wait > > * all subchannels to show up, but that may not happen because > > @@ -2547,9 +2538,23 @@ static int netvsc_probe(struct hv_device *dev, > > * -> ... -> device_add() -> ... -> __device_attach() can't get > > * the device lock, so all the subchannels can't be processed -- > > * finally netvsc_subchan_work() hangs forever. > > + * > > + * The rtnl lock also needs to be held before rndis_filter_device_add() > > + * which advertises nvsp_2_vsc_capability / sriov bit, and triggers > > + * VF NIC offering and registering. If VF NIC finished register_netdev() > > + * earlier it may cause name based config failure. > > */ > > rtnl_lock(); > > > > + nvdev = rndis_filter_device_add(dev, device_info); > > + if (IS_ERR(nvdev)) { > > + ret = PTR_ERR(nvdev); > > + netdev_err(net, "unable to add netvsc device (ret %d)\n", ret); > > + goto rndis_failed; > > In case of error rtnl won't be unlocked. Good catch! Will correct this. Thanks, - Haiyang
