Обсуждение: Bug Report: PostgreSQL 16 crashes on ALTER USER CURRENT_USER WITH PASSWORD

hi,

On 2026-01-06 14:58:52 +0100, Andrii wrote:
> PostgreSQL server crashes with a segmentation fault when executing ALTER
> USER CURRENT_USER WITH PASSWORD in PostgreSQL 16.10 and 16.11. The crash
> results in immediate termination of the backend process and forces a full
> instance restart.

> Steps to Reproduce
> 
>    1.
> 
>    Connect to PostgreSQL as a regular role (non-superuser):
> 
>    psql -U test_user -d testdb
> 
>    2.
> 
>    Execute the following command:
> 
>    ALTER USER CURRENT_USER WITH PASSWORD 'new_password';

I can't reproduce that.  Is it possible that you have some extensions loaded
that that are hooking into the command?  What is your shared_preload_libraries
set to?

Greetings,

Andres Freund

Hi,

On 2026-01-07 22:08:24 +0100, Andrii wrote:
> this problem reproduced on one instance PostgreSQL 16.10 on
> x86_64-pc-linux-gnu, compiled by gcc (GCC) 11.5.0 20240719 (Red Hat
> 11.5.0-5), 64-bit
>  with extensions
>         Name        | Version |   Schema   |
>      Description
>
--------------------+---------+------------+-----------------------------------------------------------------------------------
>  adminpack          | 2.1     | pg_catalog | administrative functions for
> PostgreSQL
>  amcheck            | 1.3     | public     | functions for verifying
> relation integrity
>  citus              | 12.1-1  | pg_catalog | Citus distributed database
>  citus_columnar     | 11.3-1  | pg_catalog | Citus Columnar extension
>  credcheck          | 3.0.0   | public     | credcheck - postgresql plain
> text credential checker
>  dblink             | 1.2     | public     | connect to other PostgreSQL
> databases from within a database
>  file_fdw           | 1.0     | public     | foreign-data wrapper for flat
> file access
>  oracle_fdw         | 1.2     | public     | foreign data wrapper for
> Oracle access
>  pageinspect        | 1.11    | public     | inspect the contents of
> database pages at a low level
>  pg_stat_statements | 1.10    | public     | track planning and execution
> statistics of all SQL statements executed
>  pgstattuple        | 1.5     | public     | show tuple-level statistics
>  plpgsql            | 1.0     | pg_catalog | PL/pgSQL procedural language
>  plpgsql_check      | 2.7     | public     | extended check for plpgsql
> functions
>  postgres_fdw       | 1.1     | public     | foreign-data wrapper for
> remote PostgreSQL servers
>  tablefunc          | 1.0     | public     | functions that manipulate
> whole tables, including crosstab
>  tds_fdw            | 2.0.3   | public     | Foreign data wrapper for
> querying a TDS database (Sybase or Microsoft SQL Server)
>  uuid-ossp          | 1.1     | public     | generate universally unique
> identifiers (UUIDs)
> 
> shared_preload_libraries='citus,pg_stat_statements'
> 
> and on other Postgres instance
> PostgreSQL 16.10 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 11.5.0
> 20240719 (Red Hat 11.5.0-5), 64-bit
>  with extensions
>         Name        | Version |   Schema   |
>      Description
>
--------------------+---------+------------+-----------------------------------------------------------------------------------
>  adminpack          | 2.1     | pg_catalog | administrative functions for
> PostgreSQL
>  dblink             | 1.2     | public     | connect to other PostgreSQL
> databases from within a database
>  file_fdw           | 1.0     | public     | foreign-data wrapper for flat
> file access
>  oracle_fdw         | 1.2     | public     | foreign data wrapper for
> Oracle access
>  pg_hint_plan       | 1.6.0   | hint_plan  |
>  pg_repack          | 1.5.2   | public     | Reorganize tables in
> PostgreSQL databases with minimal locks
>  pg_stat_monitor    | 2.1     | public     | The pg_stat_monitor is a
> PostgreSQL Query Performance Monitoring tool, based on PostgreSQL contr
>  pg_stat_statements | 1.10    | public     | track planning and execution
> statistics of all SQL statements executed
>  pgsentinel         | 1.0     | public     | active session history
>  plpgsql            | 1.0     | pg_catalog | PL/pgSQL procedural language
>  plpgsql_check      | 2.7     | public     | extended check for plpgsql
> functions
>  postgres_fdw       | 1.1     | genesis2   | foreign-data wrapper for
> remote PostgreSQL servers
>  tds_fdw            | 2.0.3   | public     | Foreign data wrapper for
> querying a TDS database (Sybase or Microsoft SQL Server)
> 
>  shared_preload_libraries='pg_stat_monitor,pg_stat_statements,pgsentinel,pg_squeeze,credcheck'

I'd suggest you look at getting a core dump, to see where the crash actually
is:
https://wiki.postgresql.org/wiki/Getting_a_stack_trace_of_a_running_PostgreSQL_backend_on_Linux/BSD

I'd also suggest trying it without a) libraries in shared_preload_libraries b)
all those extensions installed (e.g. by testing in a newly created database).

Greetings,

Andres Freund

Summary

PostgreSQL server crashes with a segmentation fault when executing ALTER USER CURRENT_USER WITH PASSWORD in PostgreSQL 16.10 and 16.11. The crash results in immediate termination of the backend process and forces a full instance restart.

Hi Andril,

I think the problem might comes from the credcheck extension. Please upgrade to version 4.3 of credcheck. Several possible crash have fixed since v3.0.

Best regards.

-- 
Gilles Darold