postgres-github.git / summary / log / commit / refs

commit    71ff232a5bc40f36365be985da72b8b6fa275811
Author:   Nathan Bossart <nathan@postgresql.org>
Date:     Thu Apr 09 18:07:06 2026 +0000

    Fix double-free in pg_stat_autovacuum_scores.
    
    Presently, relation_needs_vacanalyze() unconditionally frees the
    pgstat entry returned by pgstat_fetch_stat_tabentry_ext().  This
    behavior was first added by commit 02502c1bca to avoid memory
    leakage in autovacuum.  While this is fine for autovacuum since it
    forces stats_fetch_consistency to "none", it is not okay for other
    callers that use "cache" or "snapshot".  This manifests as a
    double-free when pg_stat_autovacuum_scores is called multiple times
    in the same transaction.
    
    To fix, add a "bool *may_free" parameter to
    pgstat_fetch_stat_tabentry_ext() that returns whether it is safe
    for the caller to explicitly pfree() the result.  If a caller would
    rather leave it to the memory context machinery to free the result,
    it can pass NULL as the "may_free" argument (or just ignore its
    value).
    
    Oversight in commit 87f61f0c82.
    
    Reported-by: Tender Wang <tndrwang@gmail.com>
    Reported-by: Alexander Lakhin <exclusion@gmail.com>
    Suggested-by: Andres Freund <andres@anarazel.de>
    Suggested-by: Tom Lane <tgl@sss.pgh.pa.us>
    Author: Sami Imseih <samimseih@gmail.com>
    Discussion: https://postgr.es/m/CAHewXNkJKdwb3D5OnksrdOqzqUnXUEMpDam1TPW0vfUkW%3D7jUw%40mail.gmail.com
    Discussion: https://postgr.es/m/5684f479-858e-4c5d-b8f5-bcf05de1f909%40gmail.com

[parent: 8030b839d3d2]