Re: [Xen-devel] [PATCH] xen-netfront: Fix hang on device removal

[Jason Andryuk]

On Thu, Apr 19, 2018 at 4:09 PM, Simon Gaiser
 wrote:
> Jason Andryuk:
>> On Thu, Apr 19, 2018 at 2:10 PM, Simon Gaiser
>>  wrote:
>>> Jason Andryuk:
 A toolstack may delete the vif frontend and backend xenstore entries
 while xen-netfront is in the removal code path.  In that case, the
 checks for xenbus_read_driver_state would return XenbusStateUnknown, and
 xennet_remove would hang indefinitely.  This hang prevents system
 shutdown.

 xennet_remove must be able to handle XenbusStateUnknown, and
 netback_changed must also wake up the wake_queue for that state as well.

 Fixes: 5b5971df3bc2 ("xen-netfront: remove warning when unloading module")
>>>
>>> I think this should go into stable since AFAIK the hanging network
>>> device can only be fixed by rebooting the guest. AFAICS this affects all
>>> 4.* branches since 5b5971df3bc2 got backported to them.
>>>
>>> Upstream commit c2d2e6738a209f0f9dffa2dc8e7292fc45360d61.
>>
>> Simon,
>>
>> Yes, I agree.  I actually submitted the request to stable earlier
>> today, so hopefully it gets added soon.
>
> Ok, great. (I checked the stable patch queue, but didn't check the
> mailing list archive).
>
>> Have you experienced this hang?
>
> Yes, it's affecting the kernel shipped by Qubes OS (see [1]).

Ok, interesting.  I tracked down this bug with older xenvm tools, and
I didn't know if libxl tools were also affected.

Greg KH added the patch to the stable queue, so it's in the process.

Regards,
Jason

Re: [Xen-devel] [PATCH] xen-netfront: Fix hang on device removal

[Jason Andryuk]

On Thu, Apr 19, 2018 at 4:09 PM, Simon Gaiser
 wrote:
> Jason Andryuk:
>> On Thu, Apr 19, 2018 at 2:10 PM, Simon Gaiser
>>  wrote:
>>> Jason Andryuk:
 A toolstack may delete the vif frontend and backend xenstore entries
 while xen-netfront is in the removal code path.  In that case, the
 checks for xenbus_read_driver_state would return XenbusStateUnknown, and
 xennet_remove would hang indefinitely.  This hang prevents system
 shutdown.

 xennet_remove must be able to handle XenbusStateUnknown, and
 netback_changed must also wake up the wake_queue for that state as well.

 Fixes: 5b5971df3bc2 ("xen-netfront: remove warning when unloading module")
>>>
>>> I think this should go into stable since AFAIK the hanging network
>>> device can only be fixed by rebooting the guest. AFAICS this affects all
>>> 4.* branches since 5b5971df3bc2 got backported to them.
>>>
>>> Upstream commit c2d2e6738a209f0f9dffa2dc8e7292fc45360d61.
>>
>> Simon,
>>
>> Yes, I agree.  I actually submitted the request to stable earlier
>> today, so hopefully it gets added soon.
>
> Ok, great. (I checked the stable patch queue, but didn't check the
> mailing list archive).
>
>> Have you experienced this hang?
>
> Yes, it's affecting the kernel shipped by Qubes OS (see [1]).

Ok, interesting.  I tracked down this bug with older xenvm tools, and
I didn't know if libxl tools were also affected.

Greg KH added the patch to the stable queue, so it's in the process.

Regards,
Jason

Re: [Xen-devel] [PATCH] xen-netfront: Fix hang on device removal

[Simon Gaiser]

Jason Andryuk:
> On Thu, Apr 19, 2018 at 2:10 PM, Simon Gaiser
>  wrote:
>> Jason Andryuk:
>>> A toolstack may delete the vif frontend and backend xenstore entries
>>> while xen-netfront is in the removal code path.  In that case, the
>>> checks for xenbus_read_driver_state would return XenbusStateUnknown, and
>>> xennet_remove would hang indefinitely.  This hang prevents system
>>> shutdown.
>>>
>>> xennet_remove must be able to handle XenbusStateUnknown, and
>>> netback_changed must also wake up the wake_queue for that state as well.
>>>
>>> Fixes: 5b5971df3bc2 ("xen-netfront: remove warning when unloading module")
>>
>> I think this should go into stable since AFAIK the hanging network
>> device can only be fixed by rebooting the guest. AFAICS this affects all
>> 4.* branches since 5b5971df3bc2 got backported to them.
>>
>> Upstream commit c2d2e6738a209f0f9dffa2dc8e7292fc45360d61.
> 
> Simon,
> 
> Yes, I agree.  I actually submitted the request to stable earlier
> today, so hopefully it gets added soon.

Ok, great. (I checked the stable patch queue, but didn't check the
mailing list archive).

> Have you experienced this hang?

Yes, it's affecting the kernel shipped by Qubes OS (see [1]).

Thanks, Simon.

[1]: https://github.com/QubesOS/qubes-issues/issues/3657



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Re: [Xen-devel] [PATCH] xen-netfront: Fix hang on device removal

[Simon Gaiser]

Jason Andryuk:
> On Thu, Apr 19, 2018 at 2:10 PM, Simon Gaiser
>  wrote:
>> Jason Andryuk:
>>> A toolstack may delete the vif frontend and backend xenstore entries
>>> while xen-netfront is in the removal code path.  In that case, the
>>> checks for xenbus_read_driver_state would return XenbusStateUnknown, and
>>> xennet_remove would hang indefinitely.  This hang prevents system
>>> shutdown.
>>>
>>> xennet_remove must be able to handle XenbusStateUnknown, and
>>> netback_changed must also wake up the wake_queue for that state as well.
>>>
>>> Fixes: 5b5971df3bc2 ("xen-netfront: remove warning when unloading module")
>>
>> I think this should go into stable since AFAIK the hanging network
>> device can only be fixed by rebooting the guest. AFAICS this affects all
>> 4.* branches since 5b5971df3bc2 got backported to them.
>>
>> Upstream commit c2d2e6738a209f0f9dffa2dc8e7292fc45360d61.
> 
> Simon,
> 
> Yes, I agree.  I actually submitted the request to stable earlier
> today, so hopefully it gets added soon.

Ok, great. (I checked the stable patch queue, but didn't check the
mailing list archive).

> Have you experienced this hang?

Yes, it's affecting the kernel shipped by Qubes OS (see [1]).

Thanks, Simon.

[1]: https://github.com/QubesOS/qubes-issues/issues/3657



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Re: [Xen-devel] [PATCH] xen-netfront: Fix hang on device removal

[Jason Andryuk]

On Thu, Apr 19, 2018 at 2:10 PM, Simon Gaiser
 wrote:
> Jason Andryuk:
>> A toolstack may delete the vif frontend and backend xenstore entries
>> while xen-netfront is in the removal code path.  In that case, the
>> checks for xenbus_read_driver_state would return XenbusStateUnknown, and
>> xennet_remove would hang indefinitely.  This hang prevents system
>> shutdown.
>>
>> xennet_remove must be able to handle XenbusStateUnknown, and
>> netback_changed must also wake up the wake_queue for that state as well.
>>
>> Fixes: 5b5971df3bc2 ("xen-netfront: remove warning when unloading module")
>
> I think this should go into stable since AFAIK the hanging network
> device can only be fixed by rebooting the guest. AFAICS this affects all
> 4.* branches since 5b5971df3bc2 got backported to them.
>
> Upstream commit c2d2e6738a209f0f9dffa2dc8e7292fc45360d61.

Simon,

Yes, I agree.  I actually submitted the request to stable earlier
today, so hopefully it gets added soon.

Have you experienced this hang?

Regards,
Jason

Re: [Xen-devel] [PATCH] xen-netfront: Fix hang on device removal

[Jason Andryuk]

On Thu, Apr 19, 2018 at 2:10 PM, Simon Gaiser
 wrote:
> Jason Andryuk:
>> A toolstack may delete the vif frontend and backend xenstore entries
>> while xen-netfront is in the removal code path.  In that case, the
>> checks for xenbus_read_driver_state would return XenbusStateUnknown, and
>> xennet_remove would hang indefinitely.  This hang prevents system
>> shutdown.
>>
>> xennet_remove must be able to handle XenbusStateUnknown, and
>> netback_changed must also wake up the wake_queue for that state as well.
>>
>> Fixes: 5b5971df3bc2 ("xen-netfront: remove warning when unloading module")
>
> I think this should go into stable since AFAIK the hanging network
> device can only be fixed by rebooting the guest. AFAICS this affects all
> 4.* branches since 5b5971df3bc2 got backported to them.
>
> Upstream commit c2d2e6738a209f0f9dffa2dc8e7292fc45360d61.

Simon,

Yes, I agree.  I actually submitted the request to stable earlier
today, so hopefully it gets added soon.

Have you experienced this hang?

Regards,
Jason

Re: [Xen-devel] [PATCH] xen-netfront: Fix hang on device removal

[Simon Gaiser]

Jason Andryuk:
> A toolstack may delete the vif frontend and backend xenstore entries
> while xen-netfront is in the removal code path.  In that case, the
> checks for xenbus_read_driver_state would return XenbusStateUnknown, and
> xennet_remove would hang indefinitely.  This hang prevents system
> shutdown.
> 
> xennet_remove must be able to handle XenbusStateUnknown, and
> netback_changed must also wake up the wake_queue for that state as well.
> 
> Fixes: 5b5971df3bc2 ("xen-netfront: remove warning when unloading module")

I think this should go into stable since AFAIK the hanging network
device can only be fixed by rebooting the guest. AFAICS this affects all
4.* branches since 5b5971df3bc2 got backported to them.

Upstream commit c2d2e6738a209f0f9dffa2dc8e7292fc45360d61.

Simon



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Re: [Xen-devel] [PATCH] xen-netfront: Fix hang on device removal

[Simon Gaiser]

Jason Andryuk:
> A toolstack may delete the vif frontend and backend xenstore entries
> while xen-netfront is in the removal code path.  In that case, the
> checks for xenbus_read_driver_state would return XenbusStateUnknown, and
> xennet_remove would hang indefinitely.  This hang prevents system
> shutdown.
> 
> xennet_remove must be able to handle XenbusStateUnknown, and
> netback_changed must also wake up the wake_queue for that state as well.
> 
> Fixes: 5b5971df3bc2 ("xen-netfront: remove warning when unloading module")

I think this should go into stable since AFAIK the hanging network
device can only be fixed by rebooting the guest. AFAICS this affects all
4.* branches since 5b5971df3bc2 got backported to them.

Upstream commit c2d2e6738a209f0f9dffa2dc8e7292fc45360d61.

Simon



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Re: [Xen-devel] [PATCH] xen-netfront: Fix hang on device removal

[Boris Ostrovsky]

On 02/28/2018 07:23 AM, Jason Andryuk wrote:
> A toolstack may delete the vif frontend and backend xenstore entries
> while xen-netfront is in the removal code path.  In that case, the
> checks for xenbus_read_driver_state would return XenbusStateUnknown, and
> xennet_remove would hang indefinitely.  This hang prevents system
> shutdown.
>
> xennet_remove must be able to handle XenbusStateUnknown, and
> netback_changed must also wake up the wake_queue for that state as well.
>
> Fixes: 5b5971df3bc2 ("xen-netfront: remove warning when unloading module")
>
> Signed-off-by: Jason Andryuk 
> Cc: Eduardo Otubo 

Reviewed-by: Boris Ostrovsky 

Re: [Xen-devel] [PATCH] xen-netfront: Fix hang on device removal

[Boris Ostrovsky]

On 02/28/2018 07:23 AM, Jason Andryuk wrote:
> A toolstack may delete the vif frontend and backend xenstore entries
> while xen-netfront is in the removal code path.  In that case, the
> checks for xenbus_read_driver_state would return XenbusStateUnknown, and
> xennet_remove would hang indefinitely.  This hang prevents system
> shutdown.
>
> xennet_remove must be able to handle XenbusStateUnknown, and
> netback_changed must also wake up the wake_queue for that state as well.
>
> Fixes: 5b5971df3bc2 ("xen-netfront: remove warning when unloading module")
>
> Signed-off-by: Jason Andryuk 
> Cc: Eduardo Otubo 

Reviewed-by: Boris Ostrovsky