From: Thomas Munro <tmunro@postgresql.org>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: Fix rare bug in read_stream.c's split IO handling.
Date: Sat, 09 Aug 2025 01:26:22 +0000
Message-ID: <E1ukYLl-001TKE-1p@gemulon.postgresql.org> (raw)
Fix rare bug in read_stream.c's split IO handling.
The internal queue of buffers could become corrupted in a rare edge case
that failed to invalidate an entry, causing a stale buffer to be
"forwarded" to StartReadBuffers(). This is a simple fix for the
immediate problem.
A small API change might be able to remove this and related fragility
entirely, but that will have to wait a bit.
Defect in commit ed0b87ca.
Bug: 19006
Backpatch-through: 18
Reported-by: Alexander Lakhin <exclusion@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Xuneng Zhou <xunengzhou@gmail.com>
Discussion: https://postgr.es/m/19006-80fcaaf69000377e%40postgresql.org
Branch
------
REL_18_STABLE
Details
-------
https://git.postgresql.org/pg/commitdiff/9110d81641696b95ea55f3a15dd0907ec0743529
Modified Files
--------------
src/backend/storage/aio/read_stream.c | 34 ++++++++++++++++++++++++++++++++++
1 file changed, 34 insertions(+)
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To: pgsql-committers@postgresql.org
Cc: tmunro@postgresql.org, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Fix rare bug in read_stream.c's split IO handling.
In-Reply-To: <E1ukYLl-001TKE-1p@gemulon.postgresql.org>
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