Re: LDAP authenticated session terminated by signal 11: Segmentationfault, PostgresSQL server terminates other active server processes - Mailing list pgsql-general

From Mike Yeap
Subject Re: LDAP authenticated session terminated by signal 11: Segmentationfault, PostgresSQL server terminates other active server processes
Date
Msg-id CAMVYW_4kwL-Y_DiHvUnpqoACsnj-V6sh+6DpDXZX1AtJqO-Rsw@mail.gmail.com
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In response to Re: LDAP authenticated session terminated by signal 11: Segmentationfault, PostgresSQL server terminates other active server processes  (Noah Misch <noah@leadboat.com>)
Responses Re: LDAP authenticated session terminated by signal 11: Segmentationfault, PostgresSQL server terminates other active server processes
List pgsql-general
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@leadboat.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@leadboat.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.

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