On 8/11/20 3:37 AM, Jason Xing wrote: > 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 :( Sure, I'll take care of this shortly. Thanks. > > Thanks, > Jason > > On Thu, Jun 4, 2020 at 9:47 PM Jason Xing <[email protected]> wrote: >> >> On Thu, Jun 4, 2020 at 9:10 PM Eric Dumazet <[email protected]> wrote: >>> >>> On Thu, Jun 4, 2020 at 2:01 AM <[email protected]> wrote: >>>> >>>> From: Jason Xing <[email protected]> >>>> >>>> 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 <[email protected]> >>>> Signed-off-by: liweishi <[email protected]> >>>> Signed-off-by: Shujin Li <[email protected]> >>> >>> 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.
