Re: [PATCH] tcp: keepalive fixes

[Enke Chen]

Hi, Eric:

Just to clarify: the issues for tcp keepalive and TCP_USER_TIMEOUT are
separate isues, and the fixes would not conflict afaik.

Thanks.  -- Enke

On Tue, Jan 12, 2021 at 11:52:43PM +0100, Eric Dumazet wrote:
> On Tue, Jan 12, 2021 at 11:48 PM Yuchung Cheng <ycheng@xxxxxxxxxx> wrote:
> >
> > On Tue, Jan 12, 2021 at 2:31 PM Enke Chen <enkechen2020@xxxxxxxxx> wrote:
> > >
> > > From: Enke Chen <enchen@xxxxxxxxxxxxxxxxxxxx>
> > >
> > > In this patch two issues with TCP keepalives are fixed:
> > >
> > > 1) TCP keepalive does not timeout when there are data waiting to be
> > >    delivered and then the connection got broken. The TCP keepalive
> > >    timeout is not evaluated in that condition.
> > hi enke
> > Do you have an example to demonstrate this issue -- in theory when
> > there is data inflight, an RTO timer should be pending (which
> > considers user-timeout setting). based on the user-timeout description
> > (man tcp), the user timeout should abort the socket per the specified
> > time after data commences. some data would help to understand the
> > issue.
> >
> 
> +1
> 
> A packetdrill test would be ideal.
> 
> Also, given that there is this ongoing issue with TCP_USER_TIMEOUT,
> lets not mix things
> or risk added work for backports to stable versions.