[stunnel-users] Periodic stunnel 4.34 core dumps on AIX 5.3

Wed Mar 9 22:30:12 CET 2011

Hello,

I have noticed that stunnel will periodically core dump on AIX 5.3. 

My configuration:
stunnel 4.34
AIX 5.3
OpenSSL 0.9.8m

After some initial investigation, I did find the following post about
stunnel
core dumps on AIX 5.3:

http://www.stunnel.org/pipermail/stunnel-users/2007-April/001528.html

Some of the core dumps were definitely due to this issue, so I rebuilt
stunnel
using the steps outlined in the post. Now I do not see the stack
overflow core
dumps, however I am still seeing other cores.

These cores have little to no valuable information in them, so I do not
have a
lot to go off of. The one thing I have noticed is that stunnel seems to
be
consuming more and more memory over time. I set up several tests to see
what 
would be causing this.

Tests:

1. Send large amounts of data through stunnel using a simple client and
server.
This seemed to have no affect on the long term memory usage of stunnel.

2. Repeatedly create and drop connections to stunnel. For this I wrote a
short
script that simply creates a connection to stunnel using telnet in a
a tight loop. I did not start anything for the stunnel instance to
connect to, 
so telnet would create a connection and get it closed immediately.

telnet --> stunnel --> nothing

The process started with a size of 836 KB and seems to increase by about
.1 to .2 KB
per connection.

$ count=1; while true; do tn localhost 10500; echo $count; count=$((
count + 1 )); done
Trying...
Escape character is '^T'.
Connection closed.
1
...
Trying...
Connected to loopback.
Escape character is '^T'.
Connection closed.
15475
Trying...
Connected to loopback.
Escape character is '^T'.
Connection closed.
15476
Trying...
Connected to loopback.
Escape character is '^T'.
Connection closed.
15477

$ monitor_process test_stunnel
Size: 836
...
Size: 2556
Size: 2564
Size: 2564
Size: 2564
Size: 2568
Size: 2572
Size: 2572
Size: 2592

I have not dug into the code yet, so I suppose that will be my next
task.
If anyone has any ideas or suggestions on what else to look at,
I would really appreciate it.

Thanks,

Paul Allex