[Mimedefang] Slave 1 stderr: Out of memory!

[Andrzej Marecki]

Occasionally I get messages like these in my /var/log/syslog:

mimedefang-multiplexor: Slave 1 stderr: Out of memory!
mimedefang-multiplexor: Slave 1 ran out of memory -- possible DoS attack due 
                        to complex MIME?

Well, I increased the limit of total size of slave processes' memory space
(MX_MAX_AS in /etc/init.d/mimedefang) to 40 kB. Should I add even more?
Or is it really a DoS attack, or... should I simply ignore such messages?

These is yet another plausible explanation of this: a memory leak.
Just look at this piece of top's output:

  PID USERNAME THR PRI NICE  SIZE   RES STATE   TIME    CPU COMMAND
13174 defang     1  30    0   38M   24M run     8:17  4.24% mimedefang.pl
 9285 defang     4  58    0 2444K 1088K sleep   1:12  0.21% mimedefang
13955 defang     1  10    0   23M   16M sleep   0:58  0.00% mimedefang.pl
 9270 defang     1  58    0 1892K  740K sleep   0:10  0.00% mimedefang-mul

Process with pid=13174 looks pretty "fatigued" - it worked for more than 8
minutes and so far has gobbled up 38Megs. A "fresher" process 13955 needed
only 23M after 1 minute of net activity. Maybe, as a quick and dirty cure,
I should merely set the minimum number of processes to keep (MX_MINIMUM) to 
0 instead of recommended 2. Each slave would get a chance to be killed during
a "quiet" period, and so to release the excessive amount of allocated memory.

Andrzej

-- 
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Andrzej Marecki                | 
Torun Centre for Astronomy     |   e-mail: amr at astro.uni.torun.pl
N. Copernicus University       |   WWW:    http://www.astro.uni.torun.pl
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