[Fedora-directory-users] glibc errors

[Bjorn Oglefjorn]

I am trying to track down the cause of some errors that have been occurring
on a number of our servers using LDAP. We have noticed that when a certain
LDAP group exceeds 65 users we begin seeing glibc errors for users in the
group. Users that are not in the group do not exhibit this behavior.

We have seen this issue on machines running Centos 4.5 x86 & x86_64 with
glibc-2.3.4-2.36 and RH4 x86_64 running glibc-2.3.4-2.25. We are running
Fedora Directory Server 1.0.4 on Centos 4.5. We have added a 3rd FDS slave
and turned up debugging but have not seen anything that appears to be
relevant in the logs on the 3rd slave.

This problem is not a 65 user limit as we have other groups with well over
65 members that do not display this behavior. We also created a new group
with identical users and it did not display this problem.

1) With 66 users in the massweb group

[root@megalon ~]# getent group massweb
*** glibc detected *** free(): invalid next size (normal): 0x09a225b0 ***
Aborted

2) After removing any user from the massweb group to reduce the total
members to 65

[root@megalon ~]# getent group massweb
massweb:x:3016:afaxon,ashairza,ccrump,jhorowit,mmarum,morendai,usmall,adroffne,afaxon,amurphre,aoliver,ayellipe,bdonohue,bdunn,beckert,blarsen,bwphilli,catanis,ccrump,chaynes,clyons,cwong,dbarber,dmuse,dnicol,edougher,egallant,ekubosia,evizcain,feeddrop,gtulonen,halokush,hbraverm,jbartus,jbrown,jhobbs,jking,jlederma,jpecora,jthayer,kbalbedi,kbeam,kginn,mbuonfig,mcrawfor,mlarsen,mlong,mwalsh,osedano,proche,prondeau,pweinber,rhorriga,rkersey,rskutins,sasaro,sbrodeur,sculver,smoriart,support,swestenh,tbaltimo,torgelfi,usmall,vvalenti

Has anyone encountered a similar problem? Any suggestions would be most
welcome.

Best regards

[Rich Megginson]

Bjorn Oglefjorn wrote:
> I am trying to track down the cause of some errors that have been 
> occurring on a number of our servers using LDAP. We have noticed that 
> when a certain LDAP group exceeds 65 users we begin seeing glibc 
> errors for users in the group. Users that are not in the group do not 
> exhibit this behavior.
>
> We have seen this issue on machines running Centos 4.5 x86 & x86_64 
> with glibc-2.3.4-2.36 and RH4 x86_64 running glibc-2.3.4-2.25. We are 
> running Fedora Directory Server 1.0.4 on Centos 4.5. We have added a 
> 3rd FDS slave and turned up debugging but have not seen anything that 
> appears to be relevant in the logs on the 3rd slave.
>
> This problem is not a 65 user limit as we have other groups with well 
> over 65 members that do not display this behavior. We also created a 
> new group with identical users and it did not display this problem.

This sounds like a problem with pam_ldap or nss_ldap.  You might want to 
report this on a CentOS list.  If you are a Red Hat customer, you can 
report it through your usual support channel.  I don't think this is a 
directory server problem.
> With 66 users in the massweb group
>
> [root@megalon ~]# getent group massweb
> *** glibc detected *** free(): invalid next size (normal): 0x09a225b0 ***
> Aborted
> After removing any user from the massweb group to reduce the total
>
> members to 65
>
> [root@megalon ~]# getent group massweb
> massweb:x:3016:afaxon,ashairza,ccrump,jhorowit,mmarum,morendai,usmall,adroffne,afaxon,amurphre,aoliver,ayellipe,bdonohue,bdunn,beckert,blarsen,bwphilli,catanis,ccrump,chaynes,clyons,cwong,dbarber,dmuse,dnicol,edougher,egallant,ekubosia,evizcain,feeddrop,gtulonen,halokush,hbraverm,jbartus,jbrown,jhobbs,jking,jlederma,jpecora,jthayer,kbalbedi,kbeam,kginn,mbuonfig,mcrawfor,mlarsen,mlong,mwalsh,osedano,proche,prondeau,pweinber,rhorriga,rkersey,rskutins,sasaro,sbrodeur,sculver,smoriart,support,swestenh,tbaltimo,torgelfi,usmall,vvalenti
>
> Has anyone encountered a similar problem? Any suggestions would be 
> most welcome.
> Best regards
>
> --
> Fedora-directory-users mailing list
> [e-mail]
> https://www.redhat.com/mailman/listinfo/fedora-directory-users

[Gordon Messmer]

Bjorn Oglefjorn wrote:
> With 66 users in the massweb group
>
> [root@megalon ~]# getent group massweb
> *** glibc detected *** free(): invalid next size (normal): 0x09a225b0 ***
> Aborted

...
> Has anyone encountered a similar problem? Any suggestions would be most 
> welcome.

Sounds kind of like a bug in glibc that was fixed in 2.3.4-2.13.  You're 
probably best off reporting this to RH via bugzilla.  I might be able to 
help you track down the precise cause of the problem, if you'd like, and 
help Red Hat get the issue resolved more quickly.

* confirm the version of glibc on that system
* install "ltrace" if necessary
* stop the "nscd" service temporarily
* run "ltrace -s 512 -S getent group massweb > /tmp/ltrace.getent 2>&1"

Email me /tmp/ltrace.getent off-list.  If there is any private info in 
/etc/ldap.conf, you'll want to clear it out of the ltrace file before 
sending it.

[Wilmer Jaramillo M.]

2007/9/27, Bjorn Oglefjorn :
> I am trying to track down the cause of some errors that have been occurring
> on a number of our servers using LDAP. We have noticed that when a certain
> LDAP group exceeds 65 users we begin seeing glibc errors for users in the
> group. Users that are not in the group do not exhibit this behavior.
>
> We have seen this issue on machines running Centos 4.5 x86 & x86_64 with
> glibc-2.3.4-2.36 and RH4 x86_64 running glibc-2.3.4-2.25. We are running
> Fedora Directory Server 1.0.4 on Centos 4.5. We have added a 3rd FDS slave
> and turned up debugging but have not seen anything that appears to be
> relevant in the logs on the 3rd slave.
>
> This problem is not a 65 user limit as we have other groups with well over
> 65 members that do not display this behavior. We also created a new group
> with identical users and it did not display this problem.
> With 66 users in the massweb group
>
> [root@megalon ~]# getent group massweb
> *** glibc detected *** free(): invalid next size (normal): 0x09a225b0 ***
> Aborted

You should disable the GLIBC internal sanity via MALLOC_CHECK_
environment variable with a zero(0) value. The RHEL4 Release Notes
show how do that, check glibc section for more information:
http://www.red-hat.com/docs/manuals/enterprise/RHEL-4-Manual/release-notes/w...