(ITS#5161) delta-syncrepl mutex lockup

[quanah@zimbra.com]

Full_Name: Quanah Gibson-Mount
Version: 2.3.37
OS: Linux 2.6
URL: ftp://ftp.openldap.org/incoming/
Submission from: (NULL) (38.104.138.6)


Several customers have found delta-syncrepl will lock up after a time.  Today it
occurred again, and this time some logging data was able to be gathered.  The
last operation logged was a MOD op.  This matches past lockups, which were also
either MOD or ADD operations.

The following files will be uploaded to the ftp site, where # will be the
assigned ITS number.

#-dbstat.delta.out.2007-10-01

which is the db_stat information for the accesslog DB

#-db_stat.out.2007-10-01

which is the db_stat information for the main DB

#-pstak.out.2007-10-01

which is the pstack information for the slapd process

Unfortunately no GDB info was retrieved this time, and reportedly gcore hung.

The most interesting part is I see no WRITE locks held in either DB, and all the
client threads are hung in a mutex.