Re: LDAP authenticated session terminated by signal 11: Segmentation fault, PostgresSQL server terminates other active server processes

Hi Noah, below is the output from one of the servers having this issue:

$ echo "select pg_backend_pid(); load 'dblink'; select pg_sleep(100)" |
psql -X &
[1] 9731

$ select pg_backend_pid(); load 'dblink'; select pg_sleep(100)
pg_backend_pid
----------------
9732
(1 row)

LOAD

$ gdb --batch --pid 9732 -ex 'info sharedlibrary ldap'

warning: .dynamic section for "/lib64/libldap-2.4.so.2" is not at the
expected address (wrong library or version mismatch?)

warning: .dynamic section for "/lib64/liblber-2.4.so.2" is not at the
expected address (wrong library or version mismatch?)
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
0x00007f1e7592dcf3 in __epoll_wait_nocancel () from /lib64/libc.so.6
From To Syms Read Shared Object Library
0x00007f1e7637d0f8 0x00007f1e763ae51c Yes (*) /lib64/libldap-2.4.so.2
0x00007f1d9f2c16d0 0x00007f1d9f2f5ae4 Yes (*)
/lib64/libldap_r-2.4.so.2
(*): Shared library is missing debugging information.

Regards,
Mike Yeap

On Thu, Mar 14, 2019 at 1:42 PM Noah Misch <noah(at)leadboat(dot)com> wrote:

> On Thu, Mar 14, 2019 at 05:18:49PM +1300, Thomas Munro wrote:
> > On Thu, Mar 7, 2019 at 4:19 PM Noah Misch <noah(at)leadboat(dot)com> wrote:
> > > Has anyone else reproduced this?
> >
> > I tried, but could not reproduce this problem on "CentOS Linux release
> > 7.6.1810 (Core)" using OpenLDAP "2.4.44-21.el7_6" (same as Mike
> > reported, what yum install is currently serving up).
>
> > When exiting the session, I was expecting the backend to crash,
> > because it had executed libldap.so code during authentication, and
> > then it had linked in libldap_r.so via libpq.so while connecting via
> > postgres_fdw. But it doesn't crash. I wonder what is different for
> > Mike; am I missing something, or is there non-determinism here?
>
> The test is deterministic. I'm guessing Mike's system is finding ldap
> libraries other than the usual system ones. Mike, would you check as
> follows?
>
> $ echo "select pg_backend_pid(); load 'dblink'; select pg_sleep(100)" |
> psql -X &
> [1] 2530123
> pg_backend_pid
> ----------------
> 2530124
> (1 row)
>
> LOAD
>
> $ gdb --batch --pid 2530124 -ex 'info sharedlibrary ldap'
> [Thread debugging using libthread_db enabled]
> Using host libthread_db library "/lib64/libthread_db.so.1".
> 0x00007ffff6303463 in __epoll_wait_nocancel () from /lib64/libc.so.6
> From To Syms Read Shared Object Library
> 0x00007ffff65e1ee0 0x00007ffff6613304 Yes (*) /lib64/libldap-2.4.so.2
> 0x00007fffe998f6d0 0x00007fffe99c3ae4 Yes (*)
> /lib64/libldap_r-2.4.so.2
> (*): Shared library is missing debugging information.
>