TCP high concurrency, RST connection cannot be released normally

[Siddh Raman Pant]

On Sat, 31 May 2025 14:02:08 +0530, oraclelinux at foxmail.com wrote:
> Problem description: Abnormal message appears in high-concurrency
> short connection, the server sends rst to the client, the client
> connection is closed, but the server connection that sends rst is
> still in ESTABLISHED state? What is the reason?
> I captured some information through bpf and confirmed that the
> server sent rst and the client status changed to close. I tracked
> the failure return of tcp_v4_send_reset and tcp_rcv_state_process
> and found that TCP RST: ACK flag = 1, but the tcp state printed here
> is the listen state, which is not consistent with the current
> connection status viewed by netstat. (Not sure if some events are
> discarded), but the tcpdump packet capture analysis shows that the
> server is indeed rst and the connection is not released.

Please mention the kernel version and userspace / distro used. While I
do not know how to fix it, a more complete picture would make the task
easier for someone who knows (and the guy reading this 8 years later).

Does the same happen on another system with same / different versions?
Worth a shot if you have a reproducer.

Thanks,
Siddh