On 10.02.20 10:40, Eugenio Perez Martin wrote:
> Hi Christian.
>
> I'm not able to reproduce the failure with eccb852f1fe6bede630e2e4f1a121a81e34354ab commit. Could you add more data? Your configuration (libvirt or qemu line), and host's dmesg output if any?
I do the following in the guest:
ping -c 200 -f somevalidip; reboot
sometimes I need to do that multiple times and sometimes I do not get a guest crash but host dmesg like
Guest moved used index from 0 to 292
xml is pretty simple
<interface type='direct'>
<mac address='52:54:00:7c:2c:f3'/>
<source dev='encbd00' mode='bridge'/>
<model type='virtio'/>
<driver name='vhost'/>
<address type='ccw' cssid='0xfe' ssid='0x0' devno='0x0001'/>
</interface>
Reverting this patch seems to make both problems go away.
>
> Thanks!
>
> On Fri, Feb 7, 2020 at 9:13 AM Christian Borntraeger <borntraeger@xxxxxxxxxx <mailto:borntraeger@xxxxxxxxxx>> wrote:
>
>
>
> On 07.02.20 08:58, Michael S. Tsirkin wrote:
> > On Fri, Feb 07, 2020 at 08:47:14AM +0100, Christian Borntraeger wrote:
> >> Also adding Cornelia.
> >>
> >>
> >> On 06.02.20 23:17, Michael S. Tsirkin wrote:
> >>> On Thu, Feb 06, 2020 at 04:12:21PM +0100, Christian Borntraeger wrote:
> >>>>
> >>>>
> >>>> On 06.02.20 15:22, eperezma@xxxxxxxxxx <mailto:eperezma@xxxxxxxxxx> wrote:
> >>>>> Hi Christian.
> >>>>>
> >>>>> Could you try this patch on top of ("38ced0208491 vhost: use batched version by default")?
> >>>>>
> >>>>> It will not solve your first random crash but it should help with the lost of network connectivity.
> >>>>>
> >>>>> Please let me know how does it goes.
> >>>>
> >>>>
> >>>> 38ced0208491 + this seem to be ok.
> >>>>
> >>>> Not sure if you can make out anything of this (and the previous git bisect log)
> >>>
> >>> Yes it does - that this is just bad split-up of patches, and there's
> >>> still a real bug that caused worse crashes :)
> >>>
> >>> So I just pushed batch-v4.
> >>> I expect that will fail, and bisect to give us
> >>> vhost: batching fetches
> >>> Can you try that please?
> >>>
> >>
> >> yes.
> >>
> >> eccb852f1fe6bede630e2e4f1a121a81e34354ab is the first bad commit
> >> commit eccb852f1fe6bede630e2e4f1a121a81e34354ab
> >> Author: Michael S. Tsirkin <mst@xxxxxxxxxx <mailto:mst@xxxxxxxxxx>>
> >> Date: Mon Oct 7 06:11:18 2019 -0400
> >>
> >> vhost: batching fetches
> >>
> >> With this patch applied, new and old code perform identically.
> >>
> >> Lots of extra optimizations are now possible, e.g.
> >> we can fetch multiple heads with copy_from/to_user now.
> >> We can get rid of maintaining the log array. Etc etc.
> >>
> >> Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx <mailto:mst@xxxxxxxxxx>>
> >>
> >> drivers/vhost/test.c | 2 +-
> >> drivers/vhost/vhost.c | 39 ++++++++++++++++++++++++++++++++++-----
> >> drivers/vhost/vhost.h | 4 +++-
> >> 3 files changed, 38 insertions(+), 7 deletions(-)
> >>
> >
> >
> > And the symptom is still the same - random crashes
> > after a bit of traffic, right?
>
> random guest crashes after a reboot of the guests. As if vhost would still
> write into now stale buffers.
>
