Re: [bisected] xfrm: TCP connection initiating PMTU discovery stalls on v3.12+

Wolfgang Walter
2014-12-08T22:20:45Z

Am Freitag, 5. Dezember 2014, 05:26:25 schrieb Eric Dumazet:
> On Fri, 2014-12-05 at 13:09 +0100, Wolfgang Walter wrote:
> > Hello,
> >
> > as reverting this patch fixes this rather annoying problem: is it
> > dangerous to revert it as a workaround until the root cause is found?
>
> Unfortunately no, this patch fixes a serious issue.
>
> We need to find the root cause of your problem instead of trying to work
> around it.
>

I only wanted to use it as local workaround here.

I looked a bit at at code. I'm not familiar with the network code, though :-).

When exactly should the gso handling with esp tunnel mode happen?

esp_output_done() calls xfrm_output_resume() and no gso handling is done.
Would be to late anyway.
esp_output() does not handle gso.
xfrm4_mode_tunnel_output() does not do any gso handling as far as I can see.

xfrm_output() (from net/xfrm/xfrm_output) does but is it called with esp
tunnel mode?

Regards,
--
Wolfgang Walter
Studentenwerk München
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