Re: commit 64ff3b938ec6782e6585a83d5459b98b0c3f6eb8 breaks rlogin

Herbert Xu
2009-02-09T07:34:01Z

On Mon, Feb 09, 2009 at 06:28:06PM +1100, Herbert Xu wrote:
> On Mon, Feb 09, 2009 at 09:13:00AM +0200, Ilpo Järvinen wrote:
> >
> > Hmm, what happens if a opposite dir ACK gets sent (it's zero sized seqno
> > range will be above urgent sequence when urg is not yet acknowledged)? So
> > we'll take the later branch after your change and send bogus 0xffff urg?
> > I think you're change might have actually broken bidir tcp completely (and
> > probably window probing as well under some conditions). Congraz, two flies
> > with a single stroke :-). You would have needed an additional check that
> > the tcb->seq is below urg...
> >
> > ...Below is a patch but Jeff might need to revert the revert first if
> > he tests with the latest Linus' tree.
>
> Good point! That would definitely explain this.

Actually, I don't see how we can have tcp_urg_mode being true
when his strace shows no OOB data at all (it only did write
and writev).

So I'm not sure if this bug is the one causing this.

Cheers,
--
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