Re: Steam is broken on new kernels

From: Guenter Roeck
Date: Tue Jun 25 2019 - 23:43:46 EST


On 6/25/19 7:29 PM, Greg Kroah-Hartman wrote:
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@xxxxxxxxxxxxxxxxx> 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...


Sounds good. Let me know if nothing shows up; I'll be happy to do it
if needed.

Guenter