/net/mpls/conf/ethX//input duplicate entry

On 6/10/15, 1:43 PM, Scott Feldman wrote:
> I'm getting this dump_stack when reloading rocker driver.  Did some
> sysctl MPLS nodes not get cleaned up on NETDEV_UNREGISTER?
>
> Steps to repro: load rocker (on system) with rocker device, rmmod
> rocker, and then modprobe rocker.  I doubt this is specific to rocker:
> and re-registration of a netdev should hit it. I am using UDEV rules
> to rename kernel's ethX to a different name.  Maybe that's what
> tripped it up?
>
On a quick look, wondering if this is because mpls driver does not seem 
to do a unregister and re-register sysctl
on device name change.

  }

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On Wed, Jun 10, 2015 at 2:58 PM, roopa <roopa@cumulusnetworks.com> wrote:
> On 6/10/15, 1:43 PM, Scott Feldman wrote:
>>
>> I'm getting this dump_stack when reloading rocker driver.  Did some
>> sysctl MPLS nodes not get cleaned up on NETDEV_UNREGISTER?
>>
>> Steps to repro: load rocker (on system) with rocker device, rmmod
>> rocker, and then modprobe rocker.  I doubt this is specific to rocker:
>> and re-registration of a netdev should hit it. I am using UDEV rules
>> to rename kernel's ethX to a different name.  Maybe that's what
>> tripped it up?
>>
> On a quick look, wondering if this is because mpls driver does not seem to
> do a unregister and re-register sysctl
> on device name change.
>
> diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
> index 7b3f732..ec21a5d 100644
> --- a/net/mpls/af_mpls.c
> +++ b/net/mpls/af_mpls.c
> @@ -564,6 +564,14 @@ static int mpls_dev_notify(struct notifier_block *this,
> unsigned long event,
>         case NETDEV_UNREGISTER:
>                 mpls_ifdown(dev);
>                 break;
> +       case NETDEV_CHANGENAME:
> +               mpls_ifdown(dev);
> +               if ((dev->type == ARPHRD_ETHER) ||
> +                   (dev->type == ARPHRD_LOOPBACK)) {
> +                       mdev = mpls_add_dev(dev);
> +                       if (IS_ERR(mdev))
> +                               return notifier_from_errno(PTR_ERR(mdev));
> +               }
>         }
>         return NOTIFY_OK;
>  }

Roopa, I tested this patch and problem goes away.  (It's missing a
break statement, BTW).  I didn't look into the correctness of the
patch, but at first glance it seems liek the right thing to do.  Maybe
breaking out the renaming portions into sub-functions could keep the
work done in NETDEV_CHANGENAME to a minimum.

Are you sending official fix?

-scott
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On 11/06/15 00:23, Scott Feldman wrote:
> On Wed, Jun 10, 2015 at 2:58 PM, roopa <roopa@cumulusnetworks.com> wrote:
>> On 6/10/15, 1:43 PM, Scott Feldman wrote:
>>>
>>> I'm getting this dump_stack when reloading rocker driver.  Did some
>>> sysctl MPLS nodes not get cleaned up on NETDEV_UNREGISTER?
>>>
>>> Steps to repro: load rocker (on system) with rocker device, rmmod
>>> rocker, and then modprobe rocker.  I doubt this is specific to rocker:
>>> and re-registration of a netdev should hit it. I am using UDEV rules
>>> to rename kernel's ethX to a different name.  Maybe that's what
>>> tripped it up?
>>>
>> On a quick look, wondering if this is because mpls driver does not seem to
>> do a unregister and re-register sysctl
>> on device name change.

Mea culpa. Thanks for looking at this.

>>
>> diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
>> index 7b3f732..ec21a5d 100644
>> --- a/net/mpls/af_mpls.c
>> +++ b/net/mpls/af_mpls.c
>> @@ -564,6 +564,14 @@ static int mpls_dev_notify(struct notifier_block *this,
>> unsigned long event,
>>          case NETDEV_UNREGISTER:
>>                  mpls_ifdown(dev);
>>                  break;
>> +       case NETDEV_CHANGENAME:
>> +               mpls_ifdown(dev);
>> +               if ((dev->type == ARPHRD_ETHER) ||
>> +                   (dev->type == ARPHRD_LOOPBACK)) {
>> +                       mdev = mpls_add_dev(dev);
>> +                       if (IS_ERR(mdev))
>> +                               return notifier_from_errno(PTR_ERR(mdev));
>> +               }
>>          }
>>          return NOTIFY_OK;
>>   }
>
> Roopa, I tested this patch and problem goes away.  (It's missing a
> break statement, BTW).  I didn't look into the correctness of the
> patch, but at first glance it seems liek the right thing to do.  Maybe
> breaking out the renaming portions into sub-functions could keep the
> work done in NETDEV_CHANGENAME to a minimum.

I agree that breaking out the sysctl registration/unregistration is a 
good idea to not have to do more work than is necessary, and to avoid 
unintended consequences (like routes using the interface being made 
unusable).

>
> Are you sending official fix?

Roopa, let me know if you'd like me to carry this forward.

Thanks,
Rob
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On 6/11/15, 5:55 AM, Robert Shearman wrote:
> On 11/06/15 00:23, Scott Feldman wrote:
>> On Wed, Jun 10, 2015 at 2:58 PM, roopa <roopa@cumulusnetworks.com> 
>> wrote:
>>> On 6/10/15, 1:43 PM, Scott Feldman wrote:
>>>>
>>>> I'm getting this dump_stack when reloading rocker driver. Did some
>>>> sysctl MPLS nodes not get cleaned up on NETDEV_UNREGISTER?
>>>>
>>>> Steps to repro: load rocker (on system) with rocker device, rmmod
>>>> rocker, and then modprobe rocker.  I doubt this is specific to rocker:
>>>> and re-registration of a netdev should hit it. I am using UDEV rules
>>>> to rename kernel's ethX to a different name.  Maybe that's what
>>>> tripped it up?
>>>>
>>> On a quick look, wondering if this is because mpls driver does not 
>>> seem to
>>> do a unregister and re-register sysctl
>>> on device name change.
>
> Mea culpa. Thanks for looking at this.
>
>>>
>>> diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
>>> index 7b3f732..ec21a5d 100644
>>> --- a/net/mpls/af_mpls.c
>>> +++ b/net/mpls/af_mpls.c
>>> @@ -564,6 +564,14 @@ static int mpls_dev_notify(struct 
>>> notifier_block *this,
>>> unsigned long event,
>>>          case NETDEV_UNREGISTER:
>>>                  mpls_ifdown(dev);
>>>                  break;
>>> +       case NETDEV_CHANGENAME:
>>> +               mpls_ifdown(dev);
>>> +               if ((dev->type == ARPHRD_ETHER) ||
>>> +                   (dev->type == ARPHRD_LOOPBACK)) {
>>> +                       mdev = mpls_add_dev(dev);
>>> +                       if (IS_ERR(mdev))
>>> +                               return 
>>> notifier_from_errno(PTR_ERR(mdev));
>>> +               }
>>>          }
>>>          return NOTIFY_OK;
>>>   }
>>
>> Roopa, I tested this patch and problem goes away.  (It's missing a
>> break statement, BTW).  I didn't look into the correctness of the
>> patch, but at first glance it seems liek the right thing to do. Maybe
>> breaking out the renaming portions into sub-functions could keep the
>> work done in NETDEV_CHANGENAME to a minimum.
>
> I agree that breaking out the sysctl registration/unregistration is a 
> good idea to not have to do more work than is necessary, and to avoid 
> unintended consequences (like routes using the interface being made 
> unusable).
>
>>
>> Are you sending official fix?
>
> Roopa, let me know if you'd like me to carry this forward.
sorry for the delay in getting back. Its going to be a busy day for me. 
And i don't know the side-effects of my changes yet.
you probably have a better handle on this. So if you can, yes please 
carry this forward.

thanks!.
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Robert Shearman <rshearma@brocade.com> writes:

> On 11/06/15 00:23, Scott Feldman wrote:
>> On Wed, Jun 10, 2015 at 2:58 PM, roopa <roopa@cumulusnetworks.com> wrote:
>>> On 6/10/15, 1:43 PM, Scott Feldman wrote:
>>>>
>>>> I'm getting this dump_stack when reloading rocker driver.  Did some
>>>> sysctl MPLS nodes not get cleaned up on NETDEV_UNREGISTER?
>>>>
>>>> Steps to repro: load rocker (on system) with rocker device, rmmod
>>>> rocker, and then modprobe rocker.  I doubt this is specific to rocker:
>>>> and re-registration of a netdev should hit it. I am using UDEV rules
>>>> to rename kernel's ethX to a different name.  Maybe that's what
>>>> tripped it up?
>>>>
>>> On a quick look, wondering if this is because mpls driver does not seem to
>>> do a unregister and re-register sysctl
>>> on device name change.
>
> Mea culpa. Thanks for looking at this.
>
>>>
>>> diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
>>> index 7b3f732..ec21a5d 100644
>>> --- a/net/mpls/af_mpls.c
>>> +++ b/net/mpls/af_mpls.c
>>> @@ -564,6 +564,14 @@ static int mpls_dev_notify(struct notifier_block *this,
>>> unsigned long event,
>>>          case NETDEV_UNREGISTER:
>>>                  mpls_ifdown(dev);
>>>                  break;
>>> +       case NETDEV_CHANGENAME:
>>> +               mpls_ifdown(dev);
>>> +               if ((dev->type == ARPHRD_ETHER) ||
>>> +                   (dev->type == ARPHRD_LOOPBACK)) {
>>> +                       mdev = mpls_add_dev(dev);
>>> +                       if (IS_ERR(mdev))
>>> +                               return notifier_from_errno(PTR_ERR(mdev));
>>> +               }
>>>          }
>>>          return NOTIFY_OK;
>>>   }
>>
>> Roopa, I tested this patch and problem goes away.  (It's missing a
>> break statement, BTW).  I didn't look into the correctness of the
>> patch, but at first glance it seems liek the right thing to do.  Maybe
>> breaking out the renaming portions into sub-functions could keep the
>> work done in NETDEV_CHANGENAME to a minimum.
>
> I agree that breaking out the sysctl registration/unregistration is a good idea
> to not have to do more work than is necessary, and to avoid unintended
> consequences (like routes using the interface being made unusable).

Yes.  It needs to be something like:

+       case NETDEV_CHANGENAME:
+		mdev = mpls_dev_get(dev);
+		if (mdev) {
+			mpls_dev_sysctl_unregister(mdev);
+			mpls_dev_sysctl_register(dev, mdev);
+		}
+		break;

Eric
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