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Re: (ITS#7705) mdb back-end segfaults sporadically with paged searches

openldap@semyon.org wrote:
> Full_Name: Semyon Chaichenets
> Version: 2.4.36
> OS: Linux 3.2.0-51-generic #77-Ubuntu SMP Wed Jul 24 20:18:19 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
> URL: ftp://ftp.openldap.org/incoming/
> Submission from: (NULL) (
> We have an issue whereby a paged-search operation causes slapd to segfault. At
> this point, I can only reproduce the issue on our production data - for which I
> cannot share coredumps. I am working on isolating the issue but would appreciate
> any help from openLDAP developers.
> The issue is triggered by the following search:
> ldapsearch -H ldap://ldaphost -b 'ou=people,dc=our,dc=org' -x -E pr=126/noprompt
> '(uid=m*)'
> We have ~59k entries starting matching uid=m*; the issue occurs unpredictably in
> the sense that it may or may not happen for filters matching other sets, but it
> can be reproduced reliably for any given filter/page size combination. On our
> setup, I could reproduce it for page-sizes 81,84,87,96,112,114,116,126.
> The issue is specific to back-mdb; backtrace points to dn2id.c:
> #0  0x00007f6d6a5ea6a1 in mdb_idscopes (op=0x7f695c110df0, isc=0x7f69692ca670)
>      at ../../../../../servers/slapd/back-mdb/dn2id.c:738
> #1  0x00007f6d6a5e399b in mdb_search (op=0x7f695c110df0, rs=0x7f69692dba00)
>      at ../../../../../servers/slapd/back-mdb/search.c:747
> [..]
> I would greatly appreciate any help you could give me with this problem.

If you backup the DB with slapcat and reload it on another server with 
slapadd, can you still reproduce the fault on the copy?
> Best,
> Semyon

   -- Howard Chu
   CTO, Symas Corp.           http://www.symas.com
   Director, Highland Sun     http://highlandsun.com/hyc/
   Chief Architect, OpenLDAP  http://www.openldap.org/project/