ldap_pvt_thread_rdwr_t  si_csn_rwlock;
        ldap_pvt_thread_mutex_t si_ops_mutex;
        ldap_pvt_thread_mutex_t si_mods_mutex;
+       ldap_pvt_thread_mutex_t si_resp_mutex;
 } syncprov_info_t;
 
 typedef struct opcookie {
                char cbuf[LDAP_PVT_CSNSTR_BUFSIZE];
                int do_check = 0, have_psearches, foundit, csn_changed = 0;
 
+               ldap_pvt_thread_mutex_lock( &si->si_resp_mutex );
+
                /* Update our context CSN */
                cbuf[0] = '\0';
                maxcsn.bv_val = cbuf;
                                        }
                                }
                        }
-                       return SLAP_CB_CONTINUE;
+                       goto leave;
                }
 
                slap_get_commit_csn( op, &maxcsn, &foundit );
                /* Don't do any processing for consumer contextCSN updates */
                if ( op->o_dont_replicate ) {
                        ldap_pvt_thread_rdwr_wunlock( &si->si_csn_rwlock );
-                       return SLAP_CB_CONTINUE;
+                       goto leave;
                }
 
                si->si_numops++;
                if ( si->si_logs && op->o_tag != LDAP_REQ_ADD ) {
                        syncprov_add_slog( op );
                }
-
+leave:         ldap_pvt_thread_mutex_unlock( &si->si_resp_mutex );
        }
        return SLAP_CB_CONTINUE;
 }
        ldap_pvt_thread_rdwr_init( &si->si_csn_rwlock );
        ldap_pvt_thread_mutex_init( &si->si_ops_mutex );
        ldap_pvt_thread_mutex_init( &si->si_mods_mutex );
+       ldap_pvt_thread_mutex_init( &si->si_resp_mutex );
 
        csn_anlist[0].an_desc = slap_schema.si_ad_entryCSN;
        csn_anlist[0].an_name = slap_schema.si_ad_entryCSN->ad_cname;
                        ber_bvarray_free( si->si_ctxcsn );
                if ( si->si_sids )
                        ch_free( si->si_sids );
+               ldap_pvt_thread_mutex_destroy( &si->si_resp_mutex );
                ldap_pvt_thread_mutex_destroy( &si->si_mods_mutex );
                ldap_pvt_thread_mutex_destroy( &si->si_ops_mutex );
                ldap_pvt_thread_rdwr_destroy( &si->si_csn_rwlock );