Re: [dpdk-dev] [PATCH v1] vhost: add sanity check for resubmiting reqs in split ring

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

On 10/14/21 10:17, Maxime Coquelin wrote:
> Hi Li,
> 
> Adding Jin Yu who introduced this function.

Looks like Jin Yu has left Intel, Chenbo, could you find someone from
the Intel SPDK team to look at it?

> On 8/27/21 07:12, Li Feng wrote:
>> When getting reqs from the avail ring, the id may exceed inflight
>> queue size. Then the dpdk will crash forever.
> 
> You need to add Fixes tag and Cc stable@dpdk.org so that it can be
> backported.
> 
>> Signed-off-by: Li Feng <fengli@smartx.com>
>> ---
>>   lib/vhost/vhost_user.c | 10 ++++++++--
>>   1 file changed, 8 insertions(+), 2 deletions(-)
>>
>> diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
>> index 29a4c9af60..f09d0f6a48 100644
>> --- a/lib/vhost/vhost_user.c
>> +++ b/lib/vhost/vhost_user.c
>> @@ -1823,8 +1823,14 @@ vhost_check_queue_inflights_split(struct 
>> virtio_net *dev,
>>       last_io = inflight_split->last_inflight_io;
>>       if (inflight_split->used_idx != used->idx) {
>> -        inflight_split->desc[last_io].inflight = 0;
>> -        rte_atomic_thread_fence(__ATOMIC_SEQ_CST);
>> +        if (unlikely(last_io >= inflight_split->desc_num)) {
>> +            VHOST_LOG_CONFIG(ERR, "last_inflight_io '%"PRIu16"' 
>> exceeds inflight "
>> +                "queue size (%"PRIu16").\n", last_io,
>> +                inflight_split->desc_num);
> 
> If such error happens, shouldn't we return RTE_VHOST_MSG_RESULT_ERR
> instead of just logging an error?
> 
>> +        } else {
>> +            inflight_split->desc[last_io].inflight = 0;
>> +            rte_atomic_thread_fence(__ATOMIC_SEQ_CST);
>> +        }
>>           inflight_split->used_idx = used->idx;
>>       }
>>
> 
> Regards,
> Maxime