Milter-greylist

> 
> So if you attach the process with gdb, where are you?
> 

Here I am:

(gdb) attach 2945
Attaching to process 2945
Reading symbols from /usr/local/bin/milter-greylist...done.
warning: .dynamic section for "/lib64/libresolv.so.2" is not at the expected address
warning: difference appears to be caused by prelink, adjusting expectations
warning: .dynamic section for "/lib64/libpthread.so.0" is not at the expected address
warning: difference appears to be caused by prelink, adjusting expectations
warning: .dynamic section for "/lib64/libnsl.so.1" is not at the expected address
warning: difference appears to be caused by prelink, adjusting expectations
warning: .dynamic section for "/lib64/libc.so.6" is not at the expected address
warning: difference appears to be caused by prelink, adjusting expectations
warning: .dynamic section for "/lib64/ld-linux-x86-64.so.2" is not at the expected address
warning: difference appears to be caused by prelink, adjusting expectations
Reading symbols from /lib64/libresolv.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib64/libresolv.so.2
Reading symbols from /lib64/libpthread.so.0...(no debugging symbols found)...done.
[Thread debugging using libthread_db enabled]
[New Thread 0x2abf9ec88940 (LWP 23910)]
[New Thread 0x2abfa148c940 (LWP 23907)]
[New Thread 0x2abfa1e8d940 (LWP 23904)]
[New Thread 0x2abfa008a940 (LWP 23901)]
[New Thread 0x2abf9e287940 (LWP 23899)]
[New Thread 0x2abfa288e940 (LWP 23895)]
[New Thread 0x2abf9b081940 (LWP 23847)]
[New Thread 0x2abfa328f940 (LWP 23746)]
[New Thread 0x2abfa3c90940 (LWP 23743)]
[New Thread 0x2abf9c483940 (LWP 23728)]
[New Thread 0x2abf9ba82940 (LWP 16424)]
[New Thread 0x2abf9a680940 (LWP 2952)]
[New Thread 0x2abf99c7f940 (LWP 2951)]
[New Thread 0x2abf9927e940 (LWP 2950)]
[New Thread 0x2abf9887d940 (LWP 2949)]
[New Thread 0x2abf97e7c940 (LWP 2946)]
Loaded symbols for /lib64/libpthread.so.0
Reading symbols from /lib64/libnsl.so.1...(no debugging symbols found)...done.
Loaded symbols for /lib64/libnsl.so.1
Reading symbols from /lib64/libc.so.6...(no debugging symbols found)...done.
Loaded symbols for /lib64/libc.so.6
Reading symbols from /lib64/ld-linux-x86-64.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib64/ld-linux-x86-64.so.2
Reading symbols from /lib64/libnss_files.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib64/libnss_files.so.2
Reading symbols from /lib64/libnss_dns.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib64/libnss_dns.so.2
warning: no loadable sections found in added symbol-file system-supplied DSO at 0x7fffe8dfd000
0x00002abf96fe2346 in poll () from /lib64/libc.so.6
(gdb) info threads
  17 Thread 0x2abf97e7c940 (LWP 2946)  0x00002abf96aec280 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
  16 Thread 0x2abf9887d940 (LWP 2949)  0x00002abf96aeeccb in accept () from /lib64/libpthread.so.0
  15 Thread 0x2abf9927e940 (LWP 2950)  0x00002abf96aeeccb in accept () from /lib64/libpthread.so.0
  14 Thread 0x2abf99c7f940 (LWP 2951)  0x00002abf96aec019 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
  13 Thread 0x2abf9a680940 (LWP 2952)  0x00002abf96aef9c8 in do_sigwait () from /lib64/libpthread.so.0
  12 Thread 0x2abf9ba82940 (LWP 16424)  0x00002abf96fdd48b in read () from /lib64/libc.so.6
  11 Thread 0x2abf9c483940 (LWP 23728)  0x00002abf96fe2346 in poll () from /lib64/libc.so.6
  10 Thread 0x2abfa3c90940 (LWP 23743)  0x00002abf96fe2346 in poll () from /lib64/libc.so.6
  9 Thread 0x2abfa328f940 (LWP 23746)  0x00002abf96fe2346 in poll () from /lib64/libc.so.6
  8 Thread 0x2abf9b081940 (LWP 23847)  0x00002abf96fe2346 in poll () from /lib64/libc.so.6
  7 Thread 0x2abfa288e940 (LWP 23895)  0x00002abf96fe2346 in poll () from /lib64/libc.so.6
  6 Thread 0x2abf9e287940 (LWP 23899)  0x00002abf96fe2346 in poll () from /lib64/libc.so.6
  5 Thread 0x2abfa008a940 (LWP 23901)  0x00002abf96fe2346 in poll () from /lib64/libc.so.6
  4 Thread 0x2abfa1e8d940 (LWP 23904)  0x00002abf96fe2346 in poll () from /lib64/libc.so.6
  3 Thread 0x2abfa148c940 (LWP 23907)  0x00002abf96fe2346 in poll () from /lib64/libc.so.6
  2 Thread 0x2abf9ec88940 (LWP 23910)  0x00002abf96fe2346 in poll () from /lib64/libc.so.6
* 1 Thread 0x2abf9726fb80 (LWP 2945)  0x00002abf96fe2346 in poll () from /lib64/libc.so.6
(gdb)

But this is the normal working milter-greylist process.
To provide useful information I have to wait till it hangs, which may be an hour,
or even two weeks to wait.

I have tried to force the hang with the command:
while :; do touch /etc/mail/greylist.conf; sleep 10; done
It let this run for two hours, no success ( I mean no hang :-( )

Please let me know if I can still give any useful information before the hang occurs on his own.