Hello folks, I've never used a jitterbug, so I hope this email goes to the right place and doesn't spam up the system.

I've been experiencing the same problem as Mark. I use OpenLDAP 2.4.23 packaged in Debian. I have a few processes that connect to ldapi:/// socket and do anonymous binds, there are one or two "no connection!" log messages each time these processes run. None of my remote connections produce these messages. This happens at very low volume, when slapd is idle. When slapd gets more utilization, maybe one or two requests per second, the noise stops.

I've spent a few hours looking at the source of OpenLDAP slapd and libldap, also Perl Net::LDAP (the client most often generating these log entries on my system). The source code for OpenLDAP looks very clean, but I'm no C expert, and I'm lost in the asynchronous nature of the connection.c. FYI, Net::LDAP doesn't use libldap - it's all Perl, no native libraries.

After hundreds of tests and various olcLogLevel settings I've finally stumbled upon something that solves the problem...

usleep(1);

I know this has to be the lamest bug report ever, but it works, please bear with me.

The first thing that tipped me to try 'usleep' was that with olcLogLevel set to "trace packets args conns stats", I get the following output:

connection_get(14) connection_get(14): got connid=1007 connection_read(14): checking for input on id=1007 * op tag 0x42, time 1283917507 * ber_get_next on fd 14 failed errno=0 (Success) connection_read(14): input error=-2 id=1007, closing. connection_closing: readying conn=1007 sd=14 for close connection_close: deferring conn=1007 sd=14 conn=1007 op=2 do_unbind conn=1007 op=2 UNBIND connection_resched: attempting closing conn=1007 sd=14 connection_close: conn=1007 sd=14 daemon: removing 14 conn=1007 fd=14 closed daemon: activity on 1 descriptor daemon: activity on: daemon: epoll: listen=8 active_threads=0 tvp=zero daemon: epoll: listen=9 active_threads=0 tvp=zero connection_get(14) connection_get(14): connection not used connection_get(14) connection_get(14): connection not used connection_read(14): no connection! connection_read(14) error connection_read(14): no connection!

The two lines I marked with asterisks are the output from the connection_input function, "op tag 0x42..." should be printed after "ber_get_next on fd 14 failed...", but it's not - so evidently this function is reentrant, the input loop is processing both the UNBIND request and the client closing the socket at the same time, and unfortunately the socket close processing came first so that connection_input thread tears down the connection.

Now with the perl scripts I tried adding a microsecond sleep just after they unbind and before they exit, it worked - haven't seen any "no connection!" logs from them for hours.

As for the libldap-client and ldapsearch commands, everytime I executed a simple 'ldapsearch -x -H ldapi:///' I'd get two "no connection!" log messages. I tried the same braindead usleep(1) solution and it worked. The following is the diff of what I changed to libldap, ldap_free_connection function in request.c:

if ( unbind ) { ldap_send_unbind( ld, lc->lconn_sb, NULL, NULL );

+ Debug( LDAP_DEBUG_TRACE, + "ldap_free_connection: sleeping after unbind\n", + 0, 0, 0 ); + usleep(1); }

Here's the last bits of output from ldapsearch with -d3 after applying this brutal "fix" to libldap:

ldap_free_connection 1 1 ldap_send_unbind ber_flush2: 7 bytes to sd 3 ldap_write: want=7, written=7 0000: 30 05 02 01 03 42 00 0....B. ldap_free_connection: sleeping after unbind ldap_free_connection: actually freed

Notice the bytes getting flushed between unbind, my dumb sleep, and "actually freed". Without the sleep it seems slapd may process the close before the unbind.