Milter-greylist

On Fri, Oct 14, 2005 at 04:15:20PM -0400, Matthew S. Cramer wrote:

> I've added another global var and am now incrementing each time
> sync_server starts and decrementing each time it returns.
> Each time milter-greylist crashes it is preceeded by the
> pthread_create errors of EAGAIN, always when trying to start a thread
> for sync_server.

I think I've made some progress.  I have 3 MX servers, and in 1 of
them I made the change above.  I was never able to get the milter to
run with sync enabled for more than a couple hours before crashing.  I
did this Friday before leaving for the weekend.  The server to which I
made the change did NOT crash all weekend, while the other two did.

Is it possible there is a race condition in sync_server, or some other
thread problem?  This is my current theory because to increment and
decrement my global var for counting sync threads, I set a mutex,
which may be resolving the real problem: the sync_server threads need
to wait on each other to finish.  There is a mutex in the code that
initiates a connection to another server but there wasn't one in the
function that handles the incoming connection.  Maybe you have to be
running more than 2 servers to see this problem?  Is anyone else using
more than 2?

I've moved my patched code over to the other 2 servers and will see
if they run all day without crashing, and will let the list know what
I find.  

My patches for reference:

bash-3.00$ diff milter-greylist.h milter-greylist-2.0.1/milter-greylist.h
96,99d95
< /* MSC */
< int syncers;
< /* MSC */
< 

bash-3.00$ diff milter-greylist.c milter-greylist-2.0.1/milter-greylist.c
586,592d585
< 
<       /* MSC */
<       extern int syncers;
< 
<       syncers = 0;
<       /* MSC */
< 

bash-3.00$ diff sync.c milter-greylist-2.0.1/sync.c
74,77d73
< /* MSC */
< pthread_mutex_t mutex1 = PTHREAD_MUTEX_INITIALIZER;
< /* MSC */
< 
826,834d821
<       /* MSC */
<       extern int syncers;
< 
<       pthread_mutex_lock( &mutex1 );
<       syncers++;
<       syslog(LOG_ERR, "Syncers: %d", syncers);
<       pthread_mutex_unlock( &mutex1 );
<       /* MSC */
< 
1003,1009d989
<       /* MSC */
<         pthread_mutex_lock( &mutex1 );
<         syncers--;
<         syslog(LOG_ERR, "Syncers: %d", syncers);
<         pthread_mutex_unlock( &mutex1 );
<       /* MSC */
< 



Optimistically,

Matt

-- 
Matthew S. Cramer <mscramer@...>          Office: 717-396-5032
Project Manager, Planning and Service Management    Fax:    717-396-5590
Armstrong World Industries, Inc.                    Cell:   717-917-7099