[SSHD-417] Memory leak in IoServiceListenerSupport.managedSessions when clients cut connections quickly

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.13.0
• Assignee: Guillaume Nodet
• Reporter: Chris Szmajda
• Created: 24/Feb/15 01:00
• Updated: 19/Dec/19 17:36
• Resolved: 17/Mar/15 17:40

Description

Raised from https://jira.atlassian.com/browse/STASH-7105

If you open and close a connection really fast it seems to hold onto lots of them in IoServiceListenerSupport

In the wild this is sometimes caused by haproxy health checks.
Can be reproduced running this python script

import socket
import sys

TCP_IP = '127.0.0.1'
TCP_PORT = 7999

def makeTestConnection():
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        s.connect((TCP_IP, TCP_PORT))
        s.close()

numConnections = 10000
if len(sys.argv) == 2:
        numConnections = int(sys.argv[1])

for i in range(numConnections):
        print(str(i))
        makeTestConnection()

If you take a heap dump afterwards you will see lots of session objects.
There seems to be a 2 minute auth timeout that gets hit and some of the sessions are removed but the majority are not removed.
Creating 10000 connections in seems to result in around 7000 of them hanging around.

Issue Links

• duplicates: SSHD-374 Nio2Acceptor never unbinding