Re: [dpdk-dev] [PATCH v2] vhost-user: drop connection on message handling failures

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 09/03/2018 12:12 PM, Ilya Maximets wrote:
> There are a lot of cases where vhost-user massage handling
> could fail and end up in a fully not recoverable state. For
> example, allocation failures of shadow used ring and batched
> copy array are not recoverable and leads to the segmentation
> faults like this on the receiving/transmission path:
> 
>    Program received signal SIGSEGV, Segmentation fault.
>    [Switching to Thread 0x7f913fecf0 (LWP 43625)]
>    in copy_desc_to_mbuf () at /lib/librte_vhost/virtio_net.c:760
>    760       batch_copy[vq->batch_copy_nb_elems].dst =
> 
> This could be easily reproduced in case of low memory or big
> number of vhost-user ports.
> 
> Fix that by propagating error to the upper layer which will
> end up with disconnection in case we can not report to
> the message sender when the error happens.
> 
> Fixes: f689586bc060 ("vhost: shadow used ring update")
> Cc:stable@dpdk.org
> 
> Signed-off-by: Ilya Maximets<i.maximets@samsung.com>
> ---
> 
> v2:
>    * Patch changed to cover most of possible failures at once. [Tiwei Bie]
> 
>   lib/librte_vhost/vhost_user.c | 51 +++++++++++++++++++++--------------
>   1 file changed, 31 insertions(+), 20 deletions(-)

Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks!
Maxime