16706f1f4d
pgstat_get_entry_ref_cached() inserts a local entry_ref with
shmem-related fields set to NULL, expecting pgstat_get_entry_ref() (its
sole caller) to fill them up before returning. If an ERROR happens
while pgstat_get_entry_ref() runs, it could be possible to finish with a
local pgstats entry partially filled.
This could lead to a crash of pgstat_gc_entry_refs(), which tolerates a
NULL shared_stats in an assertion but unconditionally dereferenced its
"dropped" and "generation" fields.
This extends 4069df21be, being a cheap insurance against NULL pointer
dereference, if some code paths of pgstat_get_entry_ref() are not able
to perform any cleanup actions (for example after a dsm_create()
throwing an ERROR).
Reviewed-by: Grigorev Jurij <ju.grigorev@ftdata.ru>
Discussion: https://postgr.es/m/aqtiKTvl519bu8-V@paquier.xyz
Backpatch-through: 15
PostgreSQL Database Management System
This directory contains the source code distribution of the PostgreSQL database management system.
PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/devel/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/devel/installation.html.
The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.