* [PATCH 0/2] virtio/s390: fix some races in virtio-ccw
@ 2018-09-21 12:46 Halil Pasic
2018-09-24 11:52 ` Christian Borntraeger
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Halil Pasic @ 2018-09-21 12:46 UTC (permalink / raw)
To: linux-s390, kvm
The trigger for the series is this bug report:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1788432
Changelog:
RFC -> v1:
* do mutual exclusion on a per device basis in ccw_io_helper()
Halil Pasic (2):
virtio/s390: avoid race on vcdev->config
virtio/s390: fix race in ccw_io_helper()
drivers/s390/virtio/virtio_ccw.c | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 deletions(-)
--
2.16.4
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 0/2] virtio/s390: fix some races in virtio-ccw
2018-09-21 12:46 [PATCH 0/2] virtio/s390: fix some races in virtio-ccw Halil Pasic
@ 2018-09-24 11:52 ` Christian Borntraeger
[not found] ` <20180921124621.43649-2-pasic@linux.ibm.com>
[not found] ` <20180921124621.43649-3-pasic@linux.ibm.com>
2 siblings, 0 replies; 6+ messages in thread
From: Christian Borntraeger @ 2018-09-24 11:52 UTC (permalink / raw)
To: Halil Pasic, Cornelia Huck, linux-s390, virtualization, kvm
Cc: Colin Ian King
Can you consider adding stable tags to the (final version of the) fixes?
On 09/21/2018 02:46 PM, Halil Pasic wrote:
> The trigger for the series is this bug report:
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1788432
>
> Changelog:
> RFC -> v1:
> * do mutual exclusion on a per device basis in ccw_io_helper()
>
> Halil Pasic (2):
> virtio/s390: avoid race on vcdev->config
> virtio/s390: fix race in ccw_io_helper()
>
> drivers/s390/virtio/virtio_ccw.c | 17 ++++++++++++++---
> 1 file changed, 14 insertions(+), 3 deletions(-)
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/2] virtio/s390: avoid race on vcdev->config
[not found] ` <80a80dc6-ccb1-f245-b367-c2f9345ca151@linux.ibm.com>
@ 2018-09-24 12:55 ` Cornelia Huck
[not found] ` <2b8982be-9066-cf08-657b-99ecf889e4a7@linux.ibm.com>
0 siblings, 1 reply; 6+ messages in thread
From: Cornelia Huck @ 2018-09-24 12:55 UTC (permalink / raw)
To: Farhan Ali, Halil Pasic, Christian Borntraeger
Cc: linux-s390, Colin Ian King, kvm, virtualization
On Fri, 21 Sep 2018 17:47:47 -0400
Farhan Ali <alifm@linux.ibm.com> wrote:
> On 09/21/2018 09:28 AM, Halil Pasic wrote:
> > Anyway I'm fine with swapping the old out and your new version in,
> > if you prefer it that way.
> >
> > If you do, would you like to have a respin?
Just send me a respin with something that you find useful :) (maybe a
mashup of our descriptions) (while at it, you could also add the
cc:stable, which I agree make sense)
> >
> > Regards,
> > Halil
> >
>
> I had been looking into this code recently, and shouldn't vcdev->status
> (function get/set_status functions) also have a lock around it? Or is it
> not possible to have a race condition on vcdev->status?
I don't think so, as status is only a byte.
>
> Thanks
> Farhan
>
>
> >>>
> >>> Let us protect the shared state using vcdev->lock.
> >>>
> >>> Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
> >>> ---
> >>> drivers/s390/virtio/virtio_ccw.c | 10 ++++++++--
> >>> 1 file changed, 8 insertions(+), 2 deletions(-)
> >>
> >
> >
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 2/2] virtio/s390: fix race in ccw_io_helper()
[not found] ` <a55df275-d982-c051-1b17-465e3a30777f@linux.ibm.com>
@ 2018-09-24 13:32 ` Cornelia Huck
2018-09-24 14:09 ` Halil Pasic
0 siblings, 1 reply; 6+ messages in thread
From: Cornelia Huck @ 2018-09-24 13:32 UTC (permalink / raw)
To: Halil Pasic; +Cc: linux-s390, Colin Ian King, kvm, virtualization
On Mon, 24 Sep 2018 14:57:26 +0200
Halil Pasic <pasic@linux.ibm.com> wrote:
> On 09/21/2018 03:30 PM, Cornelia Huck wrote:
> > On Fri, 21 Sep 2018 14:46:21 +0200
> > Halil Pasic <pasic@linux.ibm.com> wrote:
> Again, not what I tried to say. By 'This' I meant 'this race'. How
> about?
>
> """
> This race normally does not cause any problems. The operations provided
> by struct virtio_config_ops are usually invoked in a well defined sequence,
> normally don't fail, and are normally usually quite infrequent too.
s/usually/used/
>
> Yet, if some of the these operations are directly triggered via
> sysfs attributes, like in the case described by the referenced bug,
> userspace is given an opportunity to force races by increasing the
> frequency of the given operations.
> """
Fine with me.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 2/2] virtio/s390: fix race in ccw_io_helper()
2018-09-24 13:32 ` [PATCH 2/2] virtio/s390: fix race in ccw_io_helper() Cornelia Huck
@ 2018-09-24 14:09 ` Halil Pasic
0 siblings, 0 replies; 6+ messages in thread
From: Halil Pasic @ 2018-09-24 14:09 UTC (permalink / raw)
To: linux-s390, kvm
On 09/24/2018 03:32 PM, Cornelia Huck wrote:
> On Mon, 24 Sep 2018 14:57:26 +0200
> Halil Pasic <pasic@linux.ibm.com> wrote:
>
>> On 09/21/2018 03:30 PM, Cornelia Huck wrote:
>>> On Fri, 21 Sep 2018 14:46:21 +0200
>>> Halil Pasic <pasic@linux.ibm.com> wrote:
>
>> Again, not what I tried to say. By 'This' I meant 'this race'. How
>> about?
>>
>> """
>> This race normally does not cause any problems. The operations provided
>> by struct virtio_config_ops are usually invoked in a well defined sequence,
>> normally don't fail, and are normally usually quite infrequent too.
>
> s/usually/used/
Nod. Thanks!
>
>>
>> Yet, if some of the these operations are directly triggered via
>> sysfs attributes, like in the case described by the referenced bug,
>> userspace is given an opportunity to force races by increasing the
>> frequency of the given operations.
>> """
>
> Fine with me.
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/2] virtio/s390: avoid race on vcdev->config
[not found] ` <2b8982be-9066-cf08-657b-99ecf889e4a7@linux.ibm.com>
@ 2018-09-24 14:50 ` Cornelia Huck
0 siblings, 0 replies; 6+ messages in thread
From: Cornelia Huck @ 2018-09-24 14:50 UTC (permalink / raw)
To: Halil Pasic; +Cc: linux-s390, kvm, Farhan Ali, virtualization, Colin Ian King
On Mon, 24 Sep 2018 16:27:30 +0200
Halil Pasic <pasic@linux.ibm.com> wrote:
> On 09/24/2018 02:55 PM, Cornelia Huck wrote:
> > On Fri, 21 Sep 2018 17:47:47 -0400
> > Farhan Ali <alifm@linux.ibm.com> wrote:
> >
> >> On 09/21/2018 09:28 AM, Halil Pasic wrote:
> >
> >>> Anyway I'm fine with swapping the old out and your new version in,
> >>> if you prefer it that way.
> >>>
> >>> If you do, would you like to have a respin?
> >
> > Just send me a respin with something that you find useful :) (maybe a
> > mashup of our descriptions) (while at it, you could also add the
> > cc:stable, which I agree make sense)
> >
>
> Will do! I would like to go with.
>
>
> """
> This normally does not cause problems, as these are usually infrequent
> operations. However, for some devices writing to/reading from the config space
> can be triggered through sysfs attributes. For these userspace can force the
> race by increasing the frequency.
> """
Sounds good.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2018-09-24 14:50 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-09-21 12:46 [PATCH 0/2] virtio/s390: fix some races in virtio-ccw Halil Pasic
2018-09-24 11:52 ` Christian Borntraeger
[not found] ` <20180921124621.43649-2-pasic@linux.ibm.com>
[not found] ` <20180921151433.519b6687.cohuck@redhat.com>
[not found] ` <d05aa6cb-d344-37dd-f1eb-55c28fcb9c62@linux.ibm.com>
[not found] ` <80a80dc6-ccb1-f245-b367-c2f9345ca151@linux.ibm.com>
2018-09-24 12:55 ` [PATCH 1/2] virtio/s390: avoid race on vcdev->config Cornelia Huck
[not found] ` <2b8982be-9066-cf08-657b-99ecf889e4a7@linux.ibm.com>
2018-09-24 14:50 ` Cornelia Huck
[not found] ` <20180921124621.43649-3-pasic@linux.ibm.com>
[not found] ` <20180921153031.77f7693b.cohuck@redhat.com>
[not found] ` <a55df275-d982-c051-1b17-465e3a30777f@linux.ibm.com>
2018-09-24 13:32 ` [PATCH 2/2] virtio/s390: fix race in ccw_io_helper() Cornelia Huck
2018-09-24 14:09 ` Halil Pasic
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