openldap-server exit on signal 6 on 11.1 (and not in 10.3)

[joris dedieu]

Dear porters,

While moving from 10.3 to 11.1, I get an issue on openldap execution.
slapd dies (pid 29087 (slapd), uid 389: exited on signal 6) on some
complex but reproducible operations.

We worked around this bug by returning less elements from the request.
While my dear colleges are trying to write a script to reproduce the
issue, I investigate system side.


In /var/log/messages, I got slapd[4909]: stack overflow detected; terminated

The only trace I get

#0  0x0000000801f7a71a in kill () from /lib/libc.so.7
#1  0x0000000801f7a6d0 in __stack_chk_fail () from /lib/libc.so.7
#2  0x0000000801f7a640 in __stack_chk_fail () from /lib/libc.so.7
#3  0x00000000004466e6 in do_modify ()
#4  0x00000000004308d5 in connection_assign_nextid ()
#5  0x00000000004300dd in connection_read_activate ()
#6  0x0000000800956ffa in ldap_pvt_thread_pool_submit () from
/usr/local/lib/libldap_r-2.4.so.2
#7  0x0000000801c71bc5 in pthread_create () from /lib/libthr.so.3
#8  0x0000000000000000 in ?? ()

I suspect it's relative to -fstack-protector-strong  which is the
default since FreeBSD 11.0. Do you think I should rebuild all the
world this opion ?

I also thought on fdatasync

 .if ${OSVERSION} < 1101000
CFLAGS+=                -DMDB_DSYNC=O_SYNC -Dfdatasync=fsync
.endif

I'm currently investigating on this changes.

The issue disappear when slapd is compiled with debugging symbols
(WITH_DEBUG=YES). As far as I understand, this only cause -g flag to
be added to CFLAGS. Does WITH_DEBUG also disable some compiler
optimization  ?

Any thought on all this is welcomed

Joris


Openldap options :
Name           : openldap-sasl-server
Version        : 2.4.45_4
Installed on   : Thu Feb  8 16:16:45 2018 CET
Origin         : net/openldap24-server
Architecture   : FreeBSD:11:amd64
Prefix         : /usr/local
Categories     : databases net
Licenses       : OPENLDAP
Maintainer     : delphij at FreeBSD.org
WWW            : http://www.OpenLDAP.org/
Comment        : Open source LDAP server implementation
Options        :
    ACCESSLOG      : on
    ACI            : off
    AUDITLOG       : off
    BDB            : off
    COLLECT        : off
    CONSTRAINT     : off
    DDS            : off
    DEBUG          : off
    DEREF          : off
    DNSSRV         : off
    DYNACL         : off
    DYNAMIC_BACKENDS: on
    DYNGROUP       : off
    DYNLIST        : off
    FETCH          : off
    GSSAPI         : on
    KQUEUE         : off
    LASTBIND       : off
    LMPASSWD       : off
    MDB            : on
    MEMBEROF       : off
    ODBC           : off
    OUTLOOK        : off
    PASSWD         : off
    PERL           : off
    PPOLICY        : on
    PROXYCACHE     : off
    REFINT         : off
    RELAY          : off
    RETCODE        : off
    RLOOKUPS       : off
    RWM            : off
    SASL           : on
    SEQMOD         : off
    SHA2           : off
    SHELL          : off
    SLAPI          : off
    SLP            : off
    SMBPWD         : off
    SOCK           : off
    SSSVLV         : off
    SYNCPROV       : on
    TCP_WRAPPERS   : off
    TRANSLUCENT    : off
    UNIQUE         : off
    VALSORT        : off