On 22.02.2019 18:15, John Ferlan wrote:
>
>
> On 2/15/19 9:10 AM, Nikolay Shirokovskiy wrote:
>> Message of API call that creates stream and stream itself have
>> same rpc serial. This can lead to issues. If stream got error
>> immediately after creation then notification can be delivered
>> before API call reply arrived. This is possible because the
>> reply and the error message are sent from different threads
>> (rpc worker thread and event loop thread respectively). As
>> we don't check for message type in virNetClientCallCompleteAllWaitingReply
>> we complete the API call which leads to API call error [1]
>> as there is no actual reply. Later when reply arrives connection
>> will be closed due to protocol error (see check in virNetClientCallDispatchReply).
>> Let's fix virNetClientCallCompleteAllWaitingReply.
>>
>> Queue inspection on arriving VIR_NET_CONTINUE message in
>> virNetClientCallDispatchStream is safe because there we check for
>> status field also. Queue inspection on arriving VIR_NET_OK is safe
>> too as this message can not arrive before we call virFinishAbort(Finish)
>> which is not possible before API call that creates streams returns.
>> But just to be sure let's add checking message type in these places too.
>>
>> [1] error: internal error: Unexpected message type 0
>>
>> Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@xxxxxxxxxxxxx>
>> ---
>> src/rpc/virnetclient.c | 9 ++++++---
>> 1 file changed, 6 insertions(+), 3 deletions(-)
>>
>
> The commit message was hard to read, but I know it's an english is not
> the first language type thing.
>
>> diff --git a/src/rpc/virnetclient.c b/src/rpc/virnetclient.c
>> index 64855fb..0393587 100644
>> --- a/src/rpc/virnetclient.c
>> +++ b/src/rpc/virnetclient.c
>> @@ -1163,7 +1163,8 @@ static void virNetClientCallCompleteAllWaitingReply(virNetClientPtr client)
>> virNetClientCallPtr call;
>>
>> for (call = client->waitDispatch; call; call = call->next) {
>> - if (call->msg->header.prog == client->msg.header.prog &&
>> + if (call->msg->header.type == VIR_NET_STREAM &&
>
> What about VIR_NET_STREAM_HOLE ?
Here and in the other places we care only on "dummy recv"/finish/abort messages
(only such messages have expectReply flag set) and they all have type VIR_NET_STREAM.
>
> Hopefully someone with greater working knowledge of the processing of
> this code can help out here. I guess I'm just concerned about some odd
> processing case that may have expected to be called, but now wouldn't be
> because of this change.
>
> BTW: any thoughts to perhaps extracting out the common parts between the
> three places changed into it's own helper/method? e.g.:
>
> thecall->msg->header.prog == client->msg.header.prog &&
> thecall->msg->header.vers == client->msg.header.vers &&
> thecall->msg->header.serial == client->msg.header.serial &&
> thecall->expectReply
>
> and then the follow-up patch to add the additional '.type' checks?
>
I'm ok.
Nikolay
>
>> + call->msg->header.prog == client->msg.header.prog &&
>> call->msg->header.vers == client->msg.header.vers &&
>> call->msg->header.serial == client->msg.header.serial &&
>> call->expectReply)
>> @@ -1207,7 +1208,8 @@ static int virNetClientCallDispatchStream(virNetClientPtr client)
>>
>> /* Find oldest dummy message waiting for incoming data. */
>> for (thecall = client->waitDispatch; thecall; thecall = thecall->next) {
>> - if (thecall->msg->header.prog == client->msg.header.prog &&
>> + if (thecall->msg->header.type == VIR_NET_STREAM &&
>> + thecall->msg->header.prog == client->msg.header.prog &&
>> thecall->msg->header.vers == client->msg.header.vers &&
>> thecall->msg->header.serial == client->msg.header.serial &&
>> thecall->expectReply &&
>> @@ -1225,7 +1227,8 @@ static int virNetClientCallDispatchStream(virNetClientPtr client)
>> case VIR_NET_OK:
>> /* Find oldest abort/finish message. */
>> for (thecall = client->waitDispatch; thecall; thecall = thecall->next) {
>> - if (thecall->msg->header.prog == client->msg.header.prog &&
>> + if (thecall->msg->header.type == VIR_NET_STREAM &&
>> + thecall->msg->header.prog == client->msg.header.prog &&
>> thecall->msg->header.vers == client->msg.header.vers &&
>> thecall->msg->header.serial == client->msg.header.serial &&
>> thecall->expectReply &&
>>
--
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