Messages in this thread | | | From | Jason Xing <> | Date | Tue, 11 Aug 2020 18:37:46 +0800 | Subject | Re: [PATCH v2 4.19] tcp: fix TCP socks unreleased in BBR mode |
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Hi everyone,
Could anyone take a look at this issue? I believe it is of high-importance. Though Eric gave the proper patch a few months ago, the stable branch still hasn't applied or merged this fix. It seems this patch was forgotten :(
Thanks, Jason
On Thu, Jun 4, 2020 at 9:47 PM Jason Xing <kerneljasonxing@gmail.com> wrote: > > On Thu, Jun 4, 2020 at 9:10 PM Eric Dumazet <edumazet@google.com> wrote: > > > > On Thu, Jun 4, 2020 at 2:01 AM <kerneljasonxing@gmail.com> wrote: > > > > > > From: Jason Xing <kerneljasonxing@gmail.com> > > > > > > When using BBR mode, too many tcp socks cannot be released because of > > > duplicate use of the sock_hold() in the manner of tcp_internal_pacing() > > > when RTO happens. Therefore, this situation maddly increases the slab > > > memory and then constantly triggers the OOM until crash. > > > > > > Besides, in addition to BBR mode, if some mode applies pacing function, > > > it could trigger what we've discussed above, > > > > > > Reproduce procedure: > > > 0) cat /proc/slabinfo | grep TCP > > > 1) switch net.ipv4.tcp_congestion_control to bbr > > > 2) using wrk tool something like that to send packages > > > 3) using tc to increase the delay and loss to simulate the RTO case. > > > 4) cat /proc/slabinfo | grep TCP > > > 5) kill the wrk command and observe the number of objects and slabs in > > > TCP. > > > 6) at last, you could notice that the number would not decrease. > > > > > > v2: extend the timer which could cover all those related potential risks > > > (suggested by Eric Dumazet and Neal Cardwell) > > > > > > Signed-off-by: Jason Xing <kerneljasonxing@gmail.com> > > > Signed-off-by: liweishi <liweishi@kuaishou.com> > > > Signed-off-by: Shujin Li <lishujin@kuaishou.com> > > > > That is not how things work really. > > > > I will submit this properly so that stable teams do not have to guess > > how to backport this to various kernels. > > > > Changelog is misleading, this has nothing to do with BBR, we need to be precise. > > > > Thanks for your help. I can finally apply this patch into my kernel. > > Looking forward to your patchset :) > > Jason > > > Thank you.
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