dovecot - Oct 2007 - pam_ldap.so memory leaks?

Hello List,

I have a question about dovecot-1.1.0-beta3 but first I'll ramble a
little bit:

Recently I upgraded a 0.99 installation of dovecot to 1.0.5. All went
relatively smoothly until the dovecot-auth process began returning "out
of memory" after a day. There is a rather large user base here.

The current setup is using passdb pam with blocking=yes, with
pam_ldap.so handling most authentication (although in special cases I am
using a custom written pam module which I have disabled to eliminate as
the source of the leak).

The dovecot-auth process' VmRSS size grows by 4k per request and has a
limit of 256megs. Unfortunately turning blocking=yes off isn't an
option. The reason I must have it turned on is that the custom pam
module is changing the username on specific requests. I am trying to
pinpoint the memory leak (pam_ldap is my biggest suspect right now
though I'm going to try running valgrind on a test system). For now I
have set shutdown_clients=no and am restarting dovecot at regular
intervals.

Okay the question: In dovecot 1.1.0 beta3 I see that blocking=yes is now
on, no matter what. Has something been done to address potential memory
leaks in pam modules? 

Thanks,
-Andrew

On 22.10.2007, at 22.55, Flannery, Andrew wrote:
> The dovecot-auth process' VmRSS size grows by 4k per request and has a
> limit of 256megs.
The main dovecot-auth or dovecot-auth -w processes'?
> Okay the question: In dovecot 1.1.0 beta3 I see that blocking=yes  
> is now
> on, no matter what. Has something been done to address potential  
> memory
> leaks in pam modules?
# Number of auth requests to handle before destroying the process.  
This may
# be useful if PAM plugins leak memory.
#auth_worker_max_request_count = 0

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Thank you for the speedy response!
>> The dovecot-auth process' VmRSS size grows by 4k per request and
has
a 
>> limit of 256megs.
> The main dovecot-auth or dovecot-auth -w processes'?
dovecot-auth -w is the culprit.
>> Okay the question: In dovecot 1.1.0 beta3 I see that blocking=yes is 
>> now on, no matter what. Has something been done to address potential 
>> memory leaks in pam modules?
> # Number of auth requests to handle before destroying the process.  
> This may
> # be useful if PAM plugins leak memory.
> #auth_worker_max_request_count = 0
This looks promising, thanks!