Re: [Bug] Usage of stale dead_items pointer in parallel vacuum

John Naylor <johncnaylorls@gmail.com>

From: John Naylor <johncnaylorls@gmail.com>

To: Kevin Oommen Anish <kevin.o@zohocorp.com>

Cc: pgsql-bugs <pgsql-bugs@lists.postgresql.org>

Date: 2025-10-03T09:28:54Z

Lists: pgsql-bugs

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Fix reuse-after-free hazard in dead_items_reset
- 76613b539ac5 18.1 landed
- 3549ffb6afaf 17.7 landed
- 54ab74865147 19 (unreleased) landed

On Wed, Oct 1, 2025 at 10:56 PM Kevin Oommen Anish <kevin.o@zohocorp.com> wrote:
> We have discovered a bug in the dead_items_reset function in PG v17 specifically near the parallel_vacuum_reset_dead_items function() invocation. The bug is still prevalent in the latest version v18 as well. Although it was introduced in v17, it was detected while running the vacuum.sql regression tests which were introduced in PG v17.5.

I've pushed your fix, thanks for the report!

-- 
John Naylor
Amazon Web Services