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Date:   Wed, 26 Jun 2019 10:29:23 +0800
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Guenter Roeck <linux@roeck-us.net>
Cc:     Linus Torvalds <torvalds@linux-foundation.org>,
        "Pierre-Loup A. Griffais" <pgriffais@valvesoftware.com>,
        Eric Dumazet <edumazet@google.com>,
        lkml <linux-kernel@vger.kernel.org>
Subject: Re: Steam is broken on new kernels
Message-ID: <20190626022923.GA14595@kroah.com>
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On Tue, Jun 25, 2019 at 07:02:20PM -0700, Guenter Roeck wrote:
> Hi Greg,
> 
> On Sat, Jun 22, 2019 at 09:37:53AM +0200, Greg Kroah-Hartman wrote:
> > On Fri, Jun 21, 2019 at 10:28:21PM -0700, Linus Torvalds wrote:
> > > On Fri, Jun 21, 2019 at 6:03 PM Pierre-Loup A. Griffais
> > > <pgriffais@valvesoftware.com> wrote:
> > > >
> > > > I applied Eric's path to the tip of the branch and ran that kernel and
> > > > the bug didn't occur through several logout / login cycles, so things
> > > > look good at first glance. I'll keep running that kernel and report back
> > > > if anything crops up in the future, but I believe we're good, beyond
> > > > getting distros to ship this additional fix.
> > > 
> > > Good. It's now in my tree, so we can get it quickly into stable and
> > > then quickly to distributions.
> > > 
> > > Greg, it's commit b6653b3629e5 ("tcp: refine memory limit test in
> > > tcp_fragment()"), and I'm building it right now and I'll push it out
> > > in a couple of minutes assuming nothing odd is going on.
> > 
> > This looks good for 4.19 and 5.1, so I'll push out new stable kernels in
> > a bit for them.
> > 
> > But for 4.14 and older, we don't have the "hint" to know this is an
> > outbound going packet and not to apply these checks at that point in
> > time, so this patch doesn't work.
> > 
> > I'll see if I can figure anything else later this afternoon for those
> > kernels...
> > 
> 
> I may have missed it, but I don't see a fix for the problem in
> older stable branches. Any news ?
> 
> One possibility might be be to apply the part of 75c119afe14f7 which
> introduces TCP_FRAG_IN_WRITE_QUEUE and TCP_FRAG_IN_RTX_QUEUE, if that
> is acceptable.

That's what people have already discussed on the stable mailing list a
few hours ago, hopefully a patch shows up soon as I'm traveling at the
moment and can't do it myself...

thanks,

greg k-h