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: [email protected]
Fixes: e04e7a7bbd4b ("hv_netvsc: Fix a deadlock by getting rtnl lock earlier in netvsc_probe()")
Signed-off-by: Haiyang Zhang <[email protected]>
---
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;
+ }
+
+ eth_hw_addr_set(net, device_info->mac_adr);
+
if (nvdev->num_chn > 1)
schedule_work(&nvdev->subchan_work);
@@ -2788,11 +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;
}
--
2.25.1
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: [email protected]
> Fixes: e04e7a7bbd4b ("hv_netvsc: Fix a deadlock by getting rtnl lock earlier in netvsc_probe()")
> Signed-off-by: Haiyang Zhang <[email protected]>
>
> ---
> 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.
> + }
> +
> + eth_hw_addr_set(net, device_info->mac_adr);
> +
> if (nvdev->num_chn > 1)
> schedule_work(&nvdev->subchan_work);
>
> @@ -2788,11 +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;
> }
>
> -----Original Message-----
> From: Wojciech Drewek <[email protected]>
> Sent: Thursday, October 26, 2023 6:48 AM
> To: Haiyang Zhang <[email protected]>; [email protected];
> [email protected]
> Cc: KY Srinivasan <[email protected]>; [email protected]; Dexuan Cui
> <[email protected]>; [email protected]; [email protected];
> [email protected]; [email protected]; [email protected];
> [email protected]
> Subject: Re: [PATCH net] hv_netvsc: fix race of netvsc and VF
> register_netdevice
>
> [You don't often get email from [email protected]. 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: [email protected]
> > Fixes: e04e7a7bbd4b ("hv_netvsc: Fix a deadlock by getting rtnl lock earlier
> in netvsc_probe()")
> > Signed-off-by: Haiyang Zhang <[email protected]>
> >
> > ---
> > 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