On 07.02.20 08:58, Michael S. Tsirkin wrote:

On Fri, Feb 07, 2020 at 08:47:14AM +0100, Christian Borntraeger wrote:

quoted

Also adding Cornelia.


On 06.02.20 23:17, Michael S. Tsirkin wrote:

quoted

On Thu, Feb 06, 2020 at 04:12:21PM +0100, Christian Borntraeger wrote:

quoted

On 06.02.20 15:22, eperezma@redhat.com wrote:

quoted

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 [off-list ref]
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 [off-list ref]

 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.