* [PATCH] net/virtio-net: reverse unregistering on exit
@ 2017-08-22 14:59 Pierre Morel
2017-08-22 14:59 ` Pierre Morel
2017-08-22 18:17 ` Michael S. Tsirkin
0 siblings, 2 replies; 6+ messages in thread
From: Pierre Morel @ 2017-08-22 14:59 UTC (permalink / raw)
To: virtualization; +Cc: mst
Hi,
I got a problem with virtio-net in a QEMU guest.
When virtio-net is used as a module in a guest and the network is
activated, removing the virtio-net modules produces a kernel error:
[ 2375.624949] Last Breaking-Event-Address:
[ 2375.624954] [<00000000001453d4>] __cpuhp_remove_state+0x84/0x1a8
[ 2375.624959] ---[ end trace cc9fd68b89f5235a ]---
[ 2375.624966] Error: Removing state 163 which has instances left.
[ 2375.624985] ------------[ cut here ]------------
The problem is produced by an inversion in the order of unregistering
the driver and the hotplug state machine callbacks in virtio_net_driver_exit.
This patch solves the problem by first unregistering the virtio_net_driver
before unregistering the hotplug state machine callbacks.
Best regards,
Pierre Morel
Pierre Morel (1):
net/virtio-net: reverse unregistering on exit
drivers/net/virtio_net.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--
2.7.4
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH] net/virtio-net: reverse unregistering on exit
2017-08-22 14:59 [PATCH] net/virtio-net: reverse unregistering on exit Pierre Morel
@ 2017-08-22 14:59 ` Pierre Morel
2017-08-22 18:13 ` Michael S. Tsirkin
2017-08-22 18:17 ` Michael S. Tsirkin
1 sibling, 1 reply; 6+ messages in thread
From: Pierre Morel @ 2017-08-22 14:59 UTC (permalink / raw)
To: virtualization; +Cc: mst
unregister_virtio_driver should be done before the unregistering of
the hotplug state machine callbacks, otherwise the state machine still
holds some instance states at that time.
Let's first unregister the virtio_net_driver first and then the hotplug
state machine callbacks.
Signed-off-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
---
drivers/net/virtio_net.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 143d8a9..c042ffd 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -2734,9 +2734,9 @@ module_init(virtio_net_driver_init);
static __exit void virtio_net_driver_exit(void)
{
+ unregister_virtio_driver(&virtio_net_driver);
cpuhp_remove_multi_state(CPUHP_VIRT_NET_DEAD);
cpuhp_remove_multi_state(virtionet_online);
- unregister_virtio_driver(&virtio_net_driver);
}
module_exit(virtio_net_driver_exit);
--
2.7.4
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] net/virtio-net: reverse unregistering on exit
2017-08-22 14:59 ` Pierre Morel
@ 2017-08-22 18:13 ` Michael S. Tsirkin
2017-08-23 8:28 ` Pierre Morel
0 siblings, 1 reply; 6+ messages in thread
From: Michael S. Tsirkin @ 2017-08-22 18:13 UTC (permalink / raw)
To: Pierre Morel; +Cc: virtualization
On Tue, Aug 22, 2017 at 04:59:52PM +0200, Pierre Morel wrote:
> unregister_virtio_driver should be done before the unregistering of
> the hotplug state machine callbacks, otherwise the state machine still
> holds some instance states at that time.
>
> Let's first unregister the virtio_net_driver first and then the hotplug
> state machine callbacks.
>
> Signed-off-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
I'm having a deja vu.
Wasn't this fixed by
commit cfa0ebc9d6d6308564f5174ecb655b9d504b2be5
Author: Andrew Jones <drjones@redhat.com>
Date: Mon Jul 24 15:38:32 2017 +0200
virtio-net: fix module unloading
already?
> ---
> drivers/net/virtio_net.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 143d8a9..c042ffd 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -2734,9 +2734,9 @@ module_init(virtio_net_driver_init);
>
> static __exit void virtio_net_driver_exit(void)
> {
> + unregister_virtio_driver(&virtio_net_driver);
> cpuhp_remove_multi_state(CPUHP_VIRT_NET_DEAD);
> cpuhp_remove_multi_state(virtionet_online);
> - unregister_virtio_driver(&virtio_net_driver);
> }
> module_exit(virtio_net_driver_exit);
>
> --
> 2.7.4
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] net/virtio-net: reverse unregistering on exit
2017-08-22 18:13 ` Michael S. Tsirkin
@ 2017-08-23 8:28 ` Pierre Morel
0 siblings, 0 replies; 6+ messages in thread
From: Pierre Morel @ 2017-08-23 8:28 UTC (permalink / raw)
To: Michael S. Tsirkin; +Cc: virtualization
On 22/08/2017 20:13, Michael S. Tsirkin wrote:
> On Tue, Aug 22, 2017 at 04:59:52PM +0200, Pierre Morel wrote:
>> unregister_virtio_driver should be done before the unregistering of
>> the hotplug state machine callbacks, otherwise the state machine still
>> holds some instance states at that time.
>>
>> Let's first unregister the virtio_net_driver first and then the hotplug
>> state machine callbacks.
>>
>> Signed-off-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
>
> I'm having a deja vu.
>
> Wasn't this fixed by
>
> commit cfa0ebc9d6d6308564f5174ecb655b9d504b2be5
> Author: Andrew Jones <drjones@redhat.com>
> Date: Mon Jul 24 15:38:32 2017 +0200
>
> virtio-net: fix module unloading
>
> already?
hum... yes, sorry
>
>> ---
>> drivers/net/virtio_net.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
>> index 143d8a9..c042ffd 100644
>> --- a/drivers/net/virtio_net.c
>> +++ b/drivers/net/virtio_net.c
>> @@ -2734,9 +2734,9 @@ module_init(virtio_net_driver_init);
>>
>> static __exit void virtio_net_driver_exit(void)
>> {
>> + unregister_virtio_driver(&virtio_net_driver);
>> cpuhp_remove_multi_state(CPUHP_VIRT_NET_DEAD);
>> cpuhp_remove_multi_state(virtionet_online);
>> - unregister_virtio_driver(&virtio_net_driver);
>> }
>> module_exit(virtio_net_driver_exit);
>>
>> --
>> 2.7.4
>
--
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] net/virtio-net: reverse unregistering on exit
2017-08-22 14:59 [PATCH] net/virtio-net: reverse unregistering on exit Pierre Morel
2017-08-22 14:59 ` Pierre Morel
@ 2017-08-22 18:17 ` Michael S. Tsirkin
2017-08-23 8:46 ` Pierre Morel
1 sibling, 1 reply; 6+ messages in thread
From: Michael S. Tsirkin @ 2017-08-22 18:17 UTC (permalink / raw)
To: Pierre Morel; +Cc: virtualization
On Tue, Aug 22, 2017 at 04:59:51PM +0200, Pierre Morel wrote:
> Hi,
>
> I got a problem with virtio-net in a QEMU guest.
>
> When virtio-net is used as a module in a guest and the network is
> activated, removing the virtio-net modules produces a kernel error:
>
> [ 2375.624949] Last Breaking-Event-Address:
> [ 2375.624954] [<00000000001453d4>] __cpuhp_remove_state+0x84/0x1a8
> [ 2375.624959] ---[ end trace cc9fd68b89f5235a ]---
> [ 2375.624966] Error: Removing state 163 which has instances left.
> [ 2375.624985] ------------[ cut here ]------------
Which kernel do you use?
> The problem is produced by an inversion in the order of unregistering
> the driver and the hotplug state machine callbacks in virtio_net_driver_exit.
>
> This patch solves the problem by first unregistering the virtio_net_driver
> before unregistering the hotplug state machine callbacks.
>
> Best regards,
>
> Pierre Morel
>
> Pierre Morel (1):
> net/virtio-net: reverse unregistering on exit
>
> drivers/net/virtio_net.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> --
> 2.7.4
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] net/virtio-net: reverse unregistering on exit
2017-08-22 18:17 ` Michael S. Tsirkin
@ 2017-08-23 8:46 ` Pierre Morel
0 siblings, 0 replies; 6+ messages in thread
From: Pierre Morel @ 2017-08-23 8:46 UTC (permalink / raw)
To: Michael S. Tsirkin; +Cc: virtualization
On 22/08/2017 20:17, Michael S. Tsirkin wrote:
> On Tue, Aug 22, 2017 at 04:59:51PM +0200, Pierre Morel wrote:
>> Hi,
>>
>> I got a problem with virtio-net in a QEMU guest.
>>
>> When virtio-net is used as a module in a guest and the network is
>> activated, removing the virtio-net modules produces a kernel error:
>>
>> [ 2375.624949] Last Breaking-Event-Address:
>> [ 2375.624954] [<00000000001453d4>] __cpuhp_remove_state+0x84/0x1a8
>> [ 2375.624959] ---[ end trace cc9fd68b89f5235a ]---
>> [ 2375.624966] Error: Removing state 163 which has instances left.
>> [ 2375.624985] ------------[ cut here ]------------
>
> Which kernel do you use?
A too old one , 4.12.0 , I forgot to check on linux-next.
The problem has indeed been solved in between.
Sorry for the noise.
>
>
>> The problem is produced by an inversion in the order of unregistering
>> the driver and the hotplug state machine callbacks in virtio_net_driver_exit.
>>
>> This patch solves the problem by first unregistering the virtio_net_driver
>> before unregistering the hotplug state machine callbacks.
>>
>> Best regards,
>>
>> Pierre Morel
>>
>> Pierre Morel (1):
>> net/virtio-net: reverse unregistering on exit
>>
>> drivers/net/virtio_net.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> --
>> 2.7.4
>
--
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
^ permalink raw reply [flat|nested] 6+ messages in thread
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2017-08-22 14:59 [PATCH] net/virtio-net: reverse unregistering on exit Pierre Morel
2017-08-22 14:59 ` Pierre Morel
2017-08-22 18:13 ` Michael S. Tsirkin
2017-08-23 8:28 ` Pierre Morel
2017-08-22 18:17 ` Michael S. Tsirkin
2017-08-23 8:46 ` Pierre Morel
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