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

commit    c0af4eb4e71ecd4826ae6c9985f1d10ace5e1be6
Author:   Andres Freund <andres@anarazel.de>
Date:     Tue Mar 31 23:24:58 2026 +0000

    bufmgr: Fix ordering of checks in PinBuffer()
    
    The check for skip_if_not_valid added in 819dc118c0f6 was put at the start of
    the loop. A CAS loop in theory does allow to make that check in a race free
    manner. However, just after the check, there's a
        old_buf_state = WaitBufHdrUnlocked(buf);
    which introduces a race, because it would allow BM_VALID to be cleared, after
    the skip_if_not_valid check.
    
    Fix by restarting the loop after WaitBufHdrUnlocked().
    
    Reported-by: Yura Sokolov <y.sokolov@postgrespro.ru>
    Discussion: https://postgr.es/m/5bf667f3-5270-4b19-a08f-0facbecdff68@postgrespro.ru

[parent: 273d26b75e78]